Houston is finally making good on its promise to test more than 6,000 rape kits.

The Associated Press reported this week 29 people have been charged after the untested rape kits, which were completed in the fall, turned up 850 hits in the FBI’s nationwide database. Of those people, six have been convicted. Mayor Annise Parker said this is a milestone for rape survivors and their families and friends, “because it means their cases are receiving the attention they should have years ago.” In some cases, this could be as far back as 30 years.

"Now that the testing of these kits is complete, we know that it's up to us to finish the job and to seek justice for these victims," Devon Anderson, Harris Country District Attorney, added. "The ball is in our court and we will do our best to put the people who are responsible for these heinous crimes behind bars for as long as possible."

Why is there a backlog in the first place? AP cited the high cost of testing as one reason, which falls anywhere between $500 and $1,000 per kit. Though when The Houston Chronicle reported the city was backlogging kits in 2011, they cited a lack of resources. In 2002, the Houston Police Department temporarily suspended DNA testing in their crime lab "after an independent audit revealed shoddy forensic work, including unqualified personnel, lax protocols and facilities that included a roof that leaked rainwater onto evidence." Despite the lab reopening in 2006, there hasn’t been a sufficient amount of resources and personnel.

A problem, it turns out, that’s not unique to Houston. More than 12,000 kits went untested in Memphis, while more than 11,000 rape kits went untested in Detroit. Just this January, Detroit’s Wayne Country Prosecutor’s office announced a new campaign to raise $10 million in an effort to solve the cases they literally found abandoned in a warehouse. All these kits combined account for a fraction of the estimated 400,000 rape kits left untested in police departments across the country, The Daily Beast reported.

Not only is this an injustice to rape victims, it's an injustice to women everywhere. If rapists aren't caught, they’re free to commit other rapes as was the case for Helena Lazaro. Lazaro told Marie Claire after her rape kit yielded a DNA match — a kit she initially thought lost — it came out her rapist raped two additional women.

The truth is, Dr. David Lisak, a psychology professor at the University of Massachusetts who studies the subject, told the magazine, "most rapes are perpetrated by serial rapists." Some studies show the average rapist attacks as many as 11 more victims; others show they attack seven. Getting in the habit of making these kits a priority as soon as they're done will help to reduce those numbers.