CLEVELAND-- A prosecutor in Ohio's largest county says a recent acquittal in a 1993 rape case illustrates some of the challenges authorities may face while pursuing more cases based on testing of DNA from old rape kits.

Cleveland police have sent state labs about 4,000 rape kits for testing, and suburbs have added more.

The Plain Dealer ( reports the trial earlier this month in Cuyahoga County was the first based on DNA from a kit that hadn't been tested in almost 20 years.

The alleged victim testified, and evidence showed with scientific certainty that the defendant's DNA was found inside the woman. But that didn't necessarily prove there was a crime.

The prosecution says it's limited by whatever evidence is available but may tweak how it approaches similar future cases