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DNA Evidence Left at Scene Used to Create Suspect Composite in Unsolved Rapes and Murder

For Immediate Release: Monday, July 9, 2018

Detectives from the Montgomery County Police Department – Cold Case Squad continue to investigate the following assaults, rapes, and murder involving three women.  Due to similarities in these crimes, investigators believe that the same suspect is involved.  Today, detectives are releasing a composite based on the suspect’s DNA evidence that was left at two of the scenes.

Three incidents reported to police are detailed below:

  • On June 25, 1989 at approximately 10:15 p.m., the 52-year-old victim was walking on Lewis Avenue in Rockville when the suspect approached her from behind, assaulted her, and then raped her. Suspect DNA evidence was recovered in this case.
  • On September 19, 1994 at approximately 10:20 p.m., the 25-year-old victim was walking on Twinbrook Parkway when the suspect approached her from behind while armed with a knife. The suspect grabbed the victim and dragged her to the side of her residence where he attempted to rape her.  The victim successfully resisted the assault, fled, and contacted police.  No DNA evidence was able to be collected in this event.
  • On October 3, 1994, Le Bich-Thuy, age 42, was located deceased to the side of her home in the 1600 block of Martha Terrace in Rockville. The investigation by detectives revealed that Le Bich-Thuy had been assaulted, raped, and then strangled.  Investigators further determined that Le Bich-Thuy was last known to be alive at approximately 10:00 p.m. on September 28, 1994 as she left the Twinbrook Metro Station in Rockville.  Suspect DNA evidence was recovered in this case.
A DNA analysis was conducted on the evidence collected in two of these events.  Based on that analysis, it was determined that the same suspect had committed the June 25, 1989 assault and rape of the first victim and had also committed the 1994 rape and murder of Le Bich-Thuy.

Detectives recently sought the services of Parabon NanoLabs (Parabon), a DNA technology company in Virginia that specializes in DNA phenotyping, or the process of predicting physical appearance and ancestry from unidentified DNA evidence.  Using DNA evidence left by the suspect at these scenes, Parabon’s Shapshot DNA Phenotyping Service has produced what is referred to as a Snapshot composite depicting how the suspect in these cases may have looked.

How Parabon Created the Suspect Composite

Parabon’s Snapshot DNA Phenotyping Service used the DNA evidence left by the suspect at the scenes to produce trait predictions for the suspect.  Individual predictions were made for the suspect’s ancestry, eye color, hair color, skin color, freckling, and face shape.  By combining these attributes of appearance, Snapshot composites were produced depicting what the suspect might look like at a certain age and with a certain body-mass index (BMI).  The default ages and default BMIs were used because age and BMI cannot be determined from DNA.

It is important to note that Snapshot composites are scientific approximations of appearance based on DNA and are not likely to be exact replicas of appearance.  Environmental factors such as smoking, drinking, diet, and other non-environmental factors – e.g., facial hair, hairstyle, scars, etc. – cannot be predicted by DNA analysis and may cause further variation between the subject’s predicted and actual appearances.

Police Requesting the Public’s Assistance

Detectives are releasing the suspect composite with the belief that someone will recognize the suspect and provide information to investigators.   Anyone with information regarding the suspect or anyone who believes he/she may have details that might advance this investigation is urged to contact the Major Crimes Division at 240-773-5070. For those who wish to remain anonymous, Crime Solvers of Montgomery County is offering a reward of up to $10,000 for any information that leads to the arrest of the suspect. Tipsters can call Crime Solvers of Montgomery County toll-free at 1-866-411-TIPS (8477).


Map of the area where rape, attempted rape, and rape and murder occurred.Map of the area where rape, attempted rape, and rape and murder occurred. (Original Image)

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Release ID: 18-286
Media Contact: mcpnews 
Categories: homicide, sexual-offense