Process, cont.

This process is not exact, but depending upon certain parameters, studies show that if a relative is in a searched database, they will be returned in the candidate list between 86 and 100 percent of the time.^4,5

If the familial search identifies a potential family member, it is only the beginning, not the end, of an investigation. With this lead provided by DNA analysts, law enforcement can then engage in traditional police work (e.g, public records searches, criminal history reports, check alibis). In the event these efforts point to a potential suspect, officers can use any number of traditional investigative techniques, including surveillance of the person and collection of "abandoned DNA" to find out whether or not it matches their original crime scene sample.^6,7

⁴ S.P. Myers et al., Searching for first-degree familial relationships in California's Offender DNA database: Validation of a likelihood ratio-based approach, Forensic Sci. Int. Genet. (2010), doi:10.1016/j.fsigen.2010.10.010 PDF download: 340kB
⁵ Frederick R. Bieber et al., Finding Criminals Through DNA of Their Relatives, 312 Sci. 1315, 1315–16 (2006)
⁶ State of California Department of Justice, Office of the Attorney General, Press Release: California's Familial DNA Search Program Identifies Suspected "Grim Sleeper" Serial Killer » (July 07, 2010)
⁷ Jim Spellman, Using relative's DNA cracks crime, but privacy questions raised » CNN.com (Nov. 18, 2009)

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