Jump to content

User:Spu2011/Familial DNA Database Searching

From Wikipedia, the free encyclopedia


Familial DNA Database Searching Familial DNA searching is the practice of creating new investigative leads in cases where DNA evidence found at the scene of a crime (forensic profile) strongly resembles that of an existing DNA profile (offender profile) in a state DNA database but there is not an exact match. After all other leads have been exhausted, investigators may use specially developed software to compare the forensic profile to all profiles taken from a state’s DNA database in order to generate a list of those offenders most likely to be a close relative of the forensic profile. To eliminate the majority of this list, crime lab technicians conduct Y-STR analysis to confirm the familial relationships suggested by the first list. Using standard investigative techniques, authorities are then able to build a family tree. The family tree is populated from information gathered from public records and criminal justice records. Investigators rule out family members’ involvement in the crime by finding excluding factors such as sex, living out of state or being incarcerated when the crime was committed. They may also use other leads from the case, such as witness or victim’s statements, to identify a suspect. Once a suspect has been identified, investigators seek to legally obtain a DNA sample from the suspect. This suspect DNA profile is then compared to the sample found at the crime scene, in accordance with well established and constitutionally accepted practices, to definitively identify the suspect as the source of the crime scene DNA.

Familial DNA searching was first used to convict Craig Harman of manslaughter in the United Kingdom on April 19, 2004 . Currently, familial DNA searching is not conducted on a national level in the United States. States determine their own policies and decision making processes for how and when to conduct familial searches. The first familial DNA search and subsequent conviction in the United States was conducted in Denver, Colorado in 2008 using software developed under the leadership of Denver District Attorney Mitch Morrissey and Denver Police Department Crime Lab Director Gregg LaBerge. California was the first state to implement a policy for familial searching under then Attorney General, now Governor, Jerry Brown. In his role as consultant to the Familial Search Working Group of the California Department of Justice, former Alameda County Prosecutor Rock Harmon is widely considered to have been the catalyst in the adoption of familial search technology in California. The technique was used to catch the Los Angeles serial killer known as the “Grim Sleeper” in 2010 and more recently a familial search led to the arrest of 21-year-old Elvis Garcia on charges of sexual assault and false imprisonment of a woman in Santa Cruz in 2008. In March of 2011 Virginia Governor Bob McDonnell announced that Virginia would begin using familial DNA searches and other states are expected to follow.

Familial DNA searching can also be used as a tool to exonerate the falsely accused. Darryl Hunt was wrongly convicted in connection with the rape and murder of a young woman in 1984 in North Carolina. Hunt was exonerated in 2004 when a DNA database search produced a remarkably close match between a convicted felon and the forensic profile from the case. The partial match led investigators to the felon’s brother, Willard E. Brown, who confessed to the crime when confronted by police. A judge then signed an order to dismiss the case with prejudice against Hunt, ending the long ordeal for this innocent man.

In contrast to common criticism, familial DNA searching is only an investigative tactic used to identify a suspect, and is no more invasive than any other criminal investigation of this magnitude. The Ninth Circuit Court of Appeals in United States v. Pool ruled that this practice is somewhat analogous to a witness looking at a photograph of one person and stating that it looked like the perpetrator, which leads law enforcement to show the witness photos of similar looking individuals, one of whom is identified as the perpetrator. Regardless of whether familial DNA searching was the method used to identify the suspect, authorities always conduct a normal DNA test to match the suspect’s DNA with that of the DNA left at the crime scene.

For instance, investigators with Denver District Attorney’s Office successfully identified a suspect in a property theft case using a familial DNA search. In this example, the suspect’s blood left at the scene of the crime strongly resembled that of a current Department of Corrections prisoner. Using publicly available records, the investigators created a family tree. They then eliminated all the family members who were incarcerated at the time of the offense, as well as all of the females (the crime scene DNA profile was that of a male). Investigators obtained a court order to collect the suspect’s DNA, but the suspect actually volunteered to come to a police station and give a DNA sample. After providing the sample, the suspect walked free without further interrogation or detainment. Later confronted with an exact match to the forensic profile, the suspect pled guilty to criminal trespass at the first court date and was sentenced to two years probation.

References

[edit]
[edit]