'Potomac River Rapist' suspect arrested after ancestry DNA revives 1990s cold case

A suspected serial rapist and murderer accused of terrorising the Washington DC area in the 1990s, has been arrested in South Carolina after genealogy testing services made it possible for police to significantly narrow their search in the high-profile cold case.

Giles Daniel Warrick was arrested on Wednesday for a murder and rape in Washington, as well as the rapes of six people in Maryland, which all occurred within an eight-year span from 1991 to 1998.

According to Horry County jail records, Mr Warrick, 60, was denied bail on charges as a fugitive from justice.

He was arrested by US Marshals with support from police in several states. It is not known whether he has been assigned a lawyer or had a chance to enter a plea.

Police say they were able to match evidence to profiles hosted by DNA ancestry companies, which helped narrow the search to relatives of Mr Warrick and ultimately Mr Warrick himself.

Mr Warrick was working as a contractor in South Carolina after moving to the area from Maryland. Police performed a cotton-swab DNA test that they say matched evidence left at the scenes of his more than 20-year-old crimes.

The so-called Potomac River Rapist is suspected of raping 10 women, including Christine Mirzayan, an intern at the National Academy of Sciences who was bludgeoned to death by a 73-pound rock, according to police.

That attack and seven others were linked by DNA evidence. The scenes were marked by similarly violent behaviour, including throwing towels over the women before he raped them and telling them he had been stalking them, according to the FBI.

He is suspected over a string of attacks in 1991 and 1992, beginning with the 6 May 1991 rape of a 32-year-old woman inside her home in Maryland. Three other attacks occurred that year, with others in 1992 and 1996 and four more between 1997 and 1998. Victims included a teenage babysitter and women returning home from the grocery store. He is alleged to have raped at least one woman while a child was in the home.

Witnesses helped the FBI create a composite sketch of the suspect which the bureau had age-enhanced in 2011, as police began linking the cases through DNA evidence.

Genealogy testing recently was used to match forensic evidence that led to the capture of the suspected Golden State Killer, another high-profile cold case involving 13 murders and 50 rapes in California in the 1970s and '80s. Joseph James DeAngelo was arrested in 2018.