Background Paper on the Activities of the Department of Defense Senior Working Group on The Vietnam Unknown in the Tomb of the Unknown Soldiers – April 27, 1998

The Department of Defense is faced with an issue involving the possible identity of the Vietnam Unknown in the Tomb of the Unknown Soldiers in Arlington Cemetery. Although the remains were judged unidentifiable and interred in 1984, advances in forensic science now provide a capability that may allow us to identify the remains.


Efforts to account for every serviceman who did not return from the conflict in Southeast Asia are unparalleled. Through decades of field investigations, analytical assessments of seemingly unrelated data, and pushing the limits of forensic and scientific technology, we have recovered and identified the remains of 486 Americans. Cases once deemed unsolvable are now routinely solved.

Since the remains of the Vietnam Unknown were interred in 1984, DoD analysts and scientists, family members and veterans, Congress, and the American public have questioned whether we might be able to identify this individual. Mitochondrial DNA (mtDNA) testing, a tool not approved for use in forensic identification until 1995, may provide a means for making a positive identification.

The mother of First Lieutenant Michael J. Blassie, an Air Force pilot shot down in the Vietnam War, believes that the Vietnam War Unknown in the Tomb may be her son. She has requested that the Department disinter the remains and conduct mitochondrial DNA testing to confirm her contention.

Deciding whether or not to disinter requires reconciling two competing interests–the sanctity of the Tomb and our national commitment to return unaccounted for servicemen to their families. Given these two interests, is there sufficient evidence to believe that disinterring the remains could lead to an identification?

To investigate the issues thoroughly, a senior level Pentagon working group was established to make an assessment. In addition to researching records, members of this group conducted interviews with individuals who served in the An Loc area during the May-October 1972 time period. The group collected and analyzed all available information to assess:

the circumstances surrounding the case of 1Lt Blassie;
information on who else might be interred as the Vietnam Unknown;
capabilities of mtDNA to confirm an identification; and
legal implications of disinterment.

April 24, 1998
The Case of First Lieutenant Michael J. Blassie

On May 11, 1972, First Lieutenant Michael S. Blassie's A-37B aircraft was hit by ground fire, crashed, and exploded northwest of the town of An Loc, Vietnam. The wingman and a forward air controller reported seeing neither an ejection nor a parachute. A US Army helicopter surveyed the site shortly afterwards and reported seeing no survivors.

On October 31, 1972 an Armed Forces of the Republic of Vietnam (AFRVN) long-range reconnaissance foot patrol near An Loc recovered a partial set of remains and some personal effects in the vicinity of an ejection seat. The remains consisted of four ribs, part of a pelvis, and a right humerus. The effects included lLt Blassie's military identification card and currency control card, remnants of a flight suit, an ammo pouch, portions of a parachute, a pouch for a signal marker, remnants of a pistol holder, a life raft, and a small amount of currency. The patrol's report suggests they recovered the remains and personal effects from a single location, either the A-37 crash site or 1Lt Blassie's ejection site. This report, however, cannot be confirmed.

The remains and personal effects were evacuated to the US Army mortuary in Tan Son Nhut, Saigon. US military advisors to the AFRVN unit and a Vietnamese medic asserted that all recovered items were sent to the mortuary. However, some of the personal effects recovered — including 1Lt Blassie's identification card and the currency — did not arrive at the mortuary. Based on available reporting, it cannot be determined precisely how or when these items were lost or stolen.

Upon receiving the remains, the mortuary determined they were insufficient for identification. During the 1972-1975 period, the Joint Casualty Resolution Center and the mortuary made several attempts to revisit the crash site, but wartime fighting in the area prevented a thorough reinvestigation of the crash site. They also tried, without success, to recover the missing personal effects. The mortuary assigned the remains the identification number TSN (Tan Son Nhut) 0673-72, BTB (Believed to Be) Blassie, Michael Joseph. They based this BTB association primarily on the reported recovery of the identification card with ILt Blassie's name, as well as the other personal effects and the patrol's description of the crash site, all of which were consistent with 1LT Blassie's loss incident.

In 1978, the Central Identification Laboratory in Hawaii (CILHI) recommended removing the BTB status from the remains TSN 0673-72 because neither the anthropological size typing of the remains nor a blood grouping test matched ILt Blassie's profile:

Anthropological evaluation concluded the skeletal remains belonged to a 26-33 year-old with a height of between 65.2″ and 71.5″ at the time of death. 1Lt Blassie was 24 years, 1 month, and 7 days at the time of death. Military medical records indicate 1Lt Blassie's height had been recorded as 72″, 72 3/4″, and 71 inches. According to CILHI analysis, “statistical probability of the height to be over 72 inches whose humerus measured 33.5 cm is less than 1.1%.”24 April 1998

Analysis of a “small quantity of body hair, light brown in color” (also reported as “leg hair” in other analysis) found on the inside of what remained of the right trouser leg of the flight suit revealed that the blood type was 0 Negative. lLt Blassie's blood type was A Positive. While the blood grouping test itself was considered reliable at the time, subsequent tests have shown it to be only about 67% reliable, at best. Moreover, origins of the “leg hair” tested by CILHI cannot be determined for certain, or if it belonged to the wearer of the suit.

On March 23, 1979, the Chief of Air Force Mortuary, based on identification techniques and methods used at that time, concurred with CILHI's recommendation to drop the BTB Blassie status from the remains. One year later, on April 24, 1980, a three-person board appointed by the Armed Services Graves Registration Office approved deletion of the “Believed to Be” name association from the remains. Their report, dated May 7, 1980, noted the change was based on the (1) circumstances of the incident, (2) completion of search and recovery operations, (3) circumstances surrounding the actual recovery of remains, (4) identification findings presented by the U.S. Army Central Identification Laboratory, Hawaii (i.e., the anthropological size typing and blood grouping test), and (5) absence of contradictory evidence. The report designated the remains TSN 0673-72 (X- ), with the “X” number left blank. By 1984, CILHI memoranda referred to the remains as TSN 0673-72 (X-26).

In 1984, the Department of Defense, by separate action, selected the X-26 remains for interment in the Tomb of the Unknown Soldiers. In keeping with traditions of the Tomb, all records concerning X-26 were then destroyed. (Note: Records relating to 1Lt Blassie were retained in a separate casualty folder that was disassociated from the X-26 file. Additional information concerning his loss incident was obtained through record searches and interviews.)

In November 1992, members of the USCINCPAC Joint Task Force–Full Accounting (JTF-FA) investigated the Blassie case in Vietnam. A joint US-Vietnamese team interviewed a former AFRVN enlisted man who provided limited second-hand information concerning the case. JTF-FA reinvestigated the case in September 1994. The joint team surveyed the loss location, but found no signs of an aircraft crash. The team also surveyed two nearby areas identified as the recovery locations of remains in 1972. Neither site yielded any indication of an aircraft crash or human remains. No local residents had information concerning this case.

During 1995, the Department of Defense conducted a comprehensive review of all cases involving unaccounted for Americans in the Vietnam War to determine the best course of action to resolve each case. DoD analysts who reviewed the case of 1LT Blassie during this process determined that there were several possible explanations for how the ejection seat could have. been found away from the aircraft. They noted that by “accounting for the discrepancy between the loss location and the remains recovery site, the evidence supporting the possible identification of lLT Blassie's remains is enhanced.”

These analysts, unaware of the correlation between the X-26 remains interred in the Tomb and the TSN 0673-72 remains, concluded that “Prior to any other effort, the remains received in October of 1972 must be located, examined, and, if possible, tested. CILHI may, at the least, be able to determine if the bones are those of an American.” To support this recommendation, they stressed that “The recovered four ribs, one pelvis, and one humerus associated with 1LT Blassie's loss should first be re-examined to determine if new scientific methods could be used to make a positive identification. Though rejected by Tan Son Nhut Mortuary as insufficient, the remains recovered at coordinates XT716904, together with the lost ID Card and MACV Form-S may be adequate for identification.”

Who Else Could It Be?

CILHI's anthropological findings and blood grouping tests raised the possibility that the X-26 remains could belong to another American involved in one of several other U.S. losses that occurred in the An Loc area during the same time period If this were true, that meant the X-26 remains and the personal effects, including 1Lt Blassie's identification media, had to have been recovered from different or even multiple sites, contrary to what the AFRVN reported.

During 1978-1980, DoD specialists undertook an extensive effort to determine to whom else the remains might belong. A circle search of all aircrew losses during May-October 1972 within a 25-mile radius of where the remains were recovered revealed three other cases (two AH-1G Cobra attack helicopters and a C-1 30 Hercules cargo aircraft). These cases involved eight other presently unaccounted for Americans. DoD specialists compared both the remains and the physical evidence recovered with the X-26 remains against these eight individuals.

The chart below shows that although each of the eight met some of the anthropological sizing an blood grouping discriminators, only one (Candidate 2 below, who was aboard one of the Cobras) matched them all.

X-26 65.2-71.5″ 26-33 Years of Age Brown 0- Case 1853 Lt Blassie 71″,72″, &72 3/4″ 24 Years, 1 Month, 7 Days Brown A+

Case 1855 Candidate 2 69″ 30 Years, 11 Months, 11 Days Brown 0-

Candidate 3 68″ 28 Years, 4 Months, 6 Days Brown A+ Case 1837

Candidate 4 76″ 40 Years, 2 Months, 4 Days Brown A-

Candidate 5 71″ 26 Years, 5 Months, 20 Days Brown 0+

Candidate 6 71″ 38 Years, 3 Months, 16 Days Red AB+

Candidate 7 71″ 43 Years, 4 Months, 11 Days Brown 0+

Candidate 8 67″ 26 Years, 0 Months, 8 Days Brown 0+ Case 1865

Candidate 9 70″ 24 Years, 3 Months, 13 Days Brown A-April 24, 199

In Candidate 2's case, however, the physical evidence of the crash site did not correlate to his loss. For example, the AFRVN patrol reported discovering the remains near an ejection seat and returned parts of a parachute and a life raft with the remains. An AH-1 Cobra is not equipped with an ejection seat and does not normally carry parachutes or life rafts. Likewise, the C-130 does not have an ejection seat and does not normally carry rafts.

As a result of these contradictions, it was impossible to associate the X-26 remains with any of these eight other losses. A March 21, 1984 memorandum by the commander of CILHI notes that “Anthropological processing of the remains designated as TSN 0673-72 (X26) has failed to support a positive identification with any known casualty of Southeast Asia. All efforts since 4 November 1972 to establish a positive identification have proven negative. The portions of the recovered remains do not include identification criteria that can be matched exclusively to an individual and it is highly improbable that continued identification processing would be successful.” The lack of unique identifying characteristics and the state of science at that time rendered the remains unidentifiable.

Selection of the Vietnam Unknown

The decision to inter a Vietnam Unknown came in response to Congressional legislation passed in 1973. During 1981-82, the Reagan Administration began a search to find a set of remains that would fulfill the requirements of the law. There were two main selection criteria: the remains had to be those of an American serviceman and they had to be unidentifiable. Of four sets of remains originally considered eligible for interment, two were subsequently identified. The third, from Laos, could not be confirmed as an American serviceman. By process of elimination, the fourth set, X-26, was selected.

To preclude questioning the identity of the remains in the Tomb, all records concerning the nomination of candidates and selection for interment were destroyed. This practice dated from the interment of the first set of remains following World War I and was consistent with traditions established to protect the sanctity of the Tomb.

The Role of mtDNA Testing

In July 1995, the Defense Science Board approved the use of mtDNA testing as a forensic identification tool. In making its decision, the Board noted that mtDNA comparison is a scientifically recognized technique which, when used in conjunction with other evidence, strengthens a case for post-mortem identification. According to the Board, “mtDNA sequencing currently offers the best means of identifying those skeletal remains that cannot be identified through traditional means.”

According to the Armed Forces DNA Identification Laboratory (AFDIL), the

discriminatory power of mtDNA is not as strong as that of nucleaic DNA typing, but a

mtDNA profile match will generally exclude greater than 99% of the population. Nucleaic

DNA is unique to an individual, but can only be found in blood, saliva, and other body fluids that are easily destroyed and therefore unavailable with skeletal remains. In the case of the Vietnam Unknown, where analysis indicates the limited skeletal remains likely belong to one of nine individuals, mtDNA testing used in conjunction with other forensic methods could provide a compelling means of identification. Additionally, mtDNA can be used to exclude an individual in the identification process. Just as a mtDNA match can support an identification of a serviceman, a non-match can present a strong case for exclusion.

Since 1995, the Department has relied on mtDNA to assist in the identification process when all other means have failed to resolve a case. AFDIL and CILHI scientists caution that there is no assurance the mtDNA will successfully produce an identification. Although definitive results are a match or an exclusion, in some instances the results are inconclusive. There are several factors-including soil conditions, charring, age of the remains, and exposure to weather-that can destroy mtDNA. There is, however, no effective way to determine this in advance from records or by visual inspection. Only testing will determine if the bones have retained their mtDNA.

The mtDNA testing of old skeletal material requires approximately a 5-gram bone specimen (about a 1 to 1.5 cubic inch section of bone). AFDIL believes sufficient X-26 remains exist to conduct MtDNA testing, but, again, cautions there is no way to determine in advance if mtDNA can be extracted from a given bone.

AEDIL also reports that mtDNA testing would provide much more reliable results than the blood grouping analysis originally used to disassociate the X-26 remains from 1Lt Blassie. DoD medical specialists note that since the late 1970s blood grouping analysis based on hair: samples has been regarded as a highly unreliable technique. In tests conducted in the 1980s under strictly controlled laboratory conditions, researchers obtained–at best–67% reliability rate on tests of Caucasoid hair.

Any changes in controlled laboratory conditions such as increased age of the sample or contamination serve degrade further the reliability of the results.

MtDNA analysis requires a maternal family reference for comparison. Thus, for each of the nine missing servicemen considered possible matches for the X-26 remains, the Department would need to collect DNA samples (blood stains) from at least one maternal relative.

Absence of Legal Precedent

The National Cemetery Act of 1973 states that the Secretary of the Army maintains authority to operate and maintain Arlington National Cemetery. Within the cemetery, the Secretary of Defense maintains oversight authority for the Arlington Memorial Amphitheater (which includes the Tomb of the Unknowns). As stipulated in 24 U.S.C. 295(a), the Secretary of Defense is required to obtain congressional authorization to entomb remains in the Arlington Memorial Amphitheater. There are no statutes governing the disinterment of remains from the Tomb of the Unknowns.April 24, 1998

Can There Be Another Vietnam Unknown?

Modern science is rapidly bringing us to the point where we may never again have to inter a set of remains as “unknown.” Achieving this goal would represent monumental success in our effort to attain the fullest possible accounting from the war in Southeast Asia, as well as for all future conflicts.

Our comprehensive accounting efforts have made it increasingly difficult to find a set of remains about which we know very little. Even in cases where we have not made a biological identification, we often have a substantial amount of physical and circumstantial evidence to associate the remains with a few specific individuals. Consequently, any remains selected for interment would likely not be completely unknown, but rather unidentifiable using current technology and evidence.

Even with state-of-the-art forensic technology, another Vietnam-era set of remains may exist that could be deemed unidentifiable, and thus eligible for interment in the Tomb. There are sets of remains at CILHI that are unidentifiable, even using mtDNA technology.


This case involving the Tomb of the Unknown Soldiers is unique and compelling. The Tomb is a national symbol in which the entire nation has a heartfelt interest. Unfortunately, the current controversy has raised questions concerning the integrity of this national symbol. It requires us to reconcile two competing interests-the sanctity of the Tomb and our national commitment to return unaccounted for servicemen to their families. By taking action to resolve this controversy, we can preserve the integrity of the Tomb and fulfill our responsibility to the families.

Analysis of the issues raised in this paper leads to the following conclusions:

Determining the identity of the remains is consistent with our national commitment to return unaccounted for servicemen to their families.

There is no evidence to contradict judgments reached in 1980 that removed the BTB Blassie status from a set of remains, which were subsequently selected several years later as the Vietnam Unknown interred in the Tomb.

There is no reason to question the decisions reached in 1984 concerning the selection of Vietnam War remains for interment in the Tomb. Given the limited technology at the time and the information available, the X-26 remains were at that point unidentifiable.

There is no new evidence or material since 1984 that would assist in the identification process. (Two recent field investigations to the known loss locations recovered no new information.)

No statute or regulation exists that governs a decision to disinter from the Tomb of the Unknowns.

It is highly likely that the remains belong to one of the nine individuals from the An Loc area.

Disinterment for the purpose of conducting mtDNA testing will provide an effective tool for resolving the coinciding issues of preserving the integrity of an important national symbol-the Tomb of the Unknown Soldiers-and responding to a family's concerns that the remains of a loved one may lie in the tomb.

Although there is no guarantee that mtDNA would determine the identity of the remains, it is more likely than not that DoD scientists could extract a mtDNA sample from the remains given the quantity and types of remains interred in the Tomb.

MtDNA testing would, in fact, demonstrate that the remains (1) belong to one of the nine servicemen, or (2) are unidentifiable and therefore “unknown” even if the most advanced technology were utilized. Both outcomes are desirable because either one would serve to resolve the issue at hand.

Given the available evidence in this case and the Department's successful use of mtDNA testing as a forensic identification tool, utilization of this technology provides a reasonable likelihood of identifying the remains.


Based on these conclusions, there is sufficient justification to reexamine the remains to determine whether they are associated with one of the nine servicemen. Recommend disinterring the remains of the Vietnam Unknown for mtDNA testing.

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