HOUSTON - Women and minors whose rape kits languished in Houston Police Department storage rooms have filed a class action lawsuit against current and former Houston officials, alleging that the delay in testing the kits undermined their legal cases and allowed accused perpetrators to remain free.

In a complaint filed Sunday, named plaintiff Dejenay Beckwith said that if the rape kits of prior victims of her assailant had been promptly tested, she may not have been raped in 2011.

No arrest was made until 2016, when Beckwith's rape kit was finally tested and matched the DNA of her assailant, David Lee Cooper.

In late 2016, Cooper pleaded guilty to the 2002 sexual assault of a child, a 2009 sex assault and Beckwith's assault in 2011.

Houston police discovered a large cache of about 6,600 untested rape kits — some dating to the 1980s — in 2009, as it prepared to transfer materials to a newly built storage facility. It's unclear how many of the women and children whose rape kits were long untested have joined the suit, but the complaint says they are all eligible.

Rape kits are a series of DNA samplings and other evidence secured via medical procedures conducted immediately after an attack. Experts say testing them promptly and comparing them to federal DNA databases for hits is crucial because as many as half of all sex offenders are serial rapists who sometimes travel.

"When you test a kit, you not only get information about the case that's being reported to you right now," said Chris Kaiser, director of public policy and general counsel at the Texas Association Against Sexual Assault. "You start getting DNA profiles that in fact match John Doe profiles that have been in the DNA databases from years back."

In Houston, the backlog was cleared with help from a grant from the National Institute of Justice. The project, which cost about $6 million, turned up 850 matches in a national DNA database.

The Houston Forensic Science Center, which took over the city's forensic testing operations in 2014, "has worked ceaselessly to eliminate backlogs, decrease turnaround times and provide the justice system with the right answer at the right time," chief executive Dr. Peter Stout, who along with the centre is named in the lawsuit, said in a statement Tuesday.

Stout added that staffers are working to sustain a 30-day turnaround time for sex assault and all other evidence.

The suit seeks unspecified compensation for victims and a jury trial.

News from © The Associated Press, 2017