As a runner, I’ve often told my female runner friends, “Don’t run alone!” There have been cases of solo female runners being attacked on the lovely running trails we have in and around the city I live in. That advice was exactly what the father of Karina Vetrano gave to his daughter when she went out for a run along the wetlands near Howard Beach, Queens, New York. She was strangled to death and sexually assaulted that day during her run.

The case became an investigator’s nightmare with little evidence except for a stranger’s DNA on the victim’s hands, throat and cellphone. The DNA did not produce a match in any national database and the crime remained unsolved.

Frustration from the local investigative authorities caused them to seek approval to use an unusual search method called “familial DNA searches” to scour the criminal databases to identify likely close relatives of the offender to generate an evidence trail. The New York State Commission on Forensic Evidence, a member panel appointed by the governor, even developed a seven-member subcommittee to develop standards for using such familial DNA searches.

Although the perpetrator was identified eventually through other circumstantial evidence and later by an actual DNA match, the high-profile case spotlighted the potential use of familial DNA searches when DNA could not be linked directly to a suspect.

Such familial DNA searches were first introduced in Britain in 2002 and used for the first time in the United States in a California murder case in 2008, followed one year later as an evidence tool in a Colorado case. Such searches have now become a forensic application in eight states, and it has produced a helpful crime-solving trail in at least a dozen cases in the States over the last ten years. Familial DNA searches now represent a new avenue of evidence gathering in the world of forensic science.

This evidence technique uses a database “hit” of a close relative for unidentified DNA to lead authorities to a possible suspect. The close familial match to a perpetrator’s relative is less of a solid piece of evidence, and rather it represents another lead in cases to a likely suspect.

DNA testing remains the most reliable tool in forensic investigations and has been used not only to identify suspects in criminal cases but also to exonerate the wrongfully accused and convicted. As DNA technology expands from the collection and matching of samples through law enforcement agencies and evolves into DNA collections in the private sector, major concerns have been voiced regarding privacy issues and the potential for misuse.

A recent high profile cold case, labeled as the Golden State Killer, perplexed authorities in California for over four decades. Unidentified DNA that had been linked to at least a dozen murders remained unmatched to DNA in any national database. Authorities finally were permitted to search online genealogy services to match the DNA of distant relatives to narrow down the search for the perpetrator and to eventually link other evidence to identify the killer.

Such online searches are controversial to say the least, and opponents of the techniques site the Fourth Amendment for prohibition of unreasonable search and the 14^th Amendment’s equal protection clause as reason to prevent use of familial DNA searches.

This crime-solving technique, although used in some particularly vexing cases, has not been thoroughly tested in the courts as yet, and it will be interesting to see how the legal issues surrounding this relatively new forensic tool evolve.

Thoughts? Comments? I’d love to hear them!