South Florida's three top state prosecutors say they plan to continue testing DNA evidence for convicts who have credible innocence claims even though a state law says they can stop looking at old cases after Oct. 1.

''How can you put a deadline on innocence?'' asked Miami-Dade State Attorney Katherine Fernandez Rundle.

Broward State Attorney Michael Satz and Palm Beach County Prosecutor Barry Krischer have taken the same position, to the delight of prisoners' advocates who say the improved technology has the potential to free the wrongly convicted.

The prosecutors say they won't test all inmates -- only those who can show that the evidence could positively eliminate the convict as the offender. Judges will continue to have the ultimate authority in deciding whether a test must be conducted.

DNA evidence is a scientific footprint now used commonly in linking suspects to crimes through hair or bodily fluids. Since technology has improved, defense lawyers have used such tests to exonerate some people who were convicted before the technology was readily available. The Innocence Project at Yeshiva University's Cordozo Law School in New York has documented 131 such cases, including two high-profile cases involving Broward County inmates.

Led by DNA expert Barry Scheck, the Innocence Project has brought public attention to the issue. But time has been running out for inmates who want their DNA tested.

LAW'S PROVISIONS

A 2001 law, sponsored by state Sen. Alex Villalobos, R-Miami, gives convicts two years to file court petitions to have DNA evidence tested. Inmates whose convictions are older than two years have until Oct. 1 under the law.

''There's just too many cases,'' Scheck said. Even another year wouldn't clear all of them, he said.

Advocates say they have worked as fast as they can -- separating valid claims from the frivolous or unprovable -- but still have 600 cases to review. Last week, an influential committee of lawyers and judges voted to ask the Florida Supreme Court to extend the Oct. 1 deadline for another year, something the court could do without ruling on the law's constitutionality.

An extension will be important regardless of whether prosecutors agree individually to extend it because it will keep law enforcement from destroying old evidence, lawyers say.

The issue gained attention in Florida when DNA evidence led to the exoneration of Frank Lee Smith, a Broward man convicted of a 1985 rape and murder. He died of cancer on Death Row before he was cleared.

Jerry Frank Townsend, also from Broward, was cleared of rape and murder after serving 22 years in prison.

Lawyers say many cases are old, making the task of finding evidence and reviewing written records difficult.

''We've had cases from 1959,'' said Catherine Arcabascio, co-director of the Florida Innocence Project, based at Nova Southeastern University in Davie.

''One of the ironies is that giving [us] time to screen will lesson the burden on courts,'' said Craig Trocino, the project's other co-director.

In addition to advocacy organizations and private attorneys, many inmates have filed claims directly to the courts, working as their own lawyers.

''We look at those motions as closely as we do those requests by defendants with attorneys,'' said Carolyn McCann, the lead appeals lawyer in the Broward State Attorney's Office.

McCann said most of the 50 requests her office has received have been filed by inmates acting as their own attorneys.

TWO QUESTIONS

McCann and other prosecutors say they will consider two questions:

• Is identity of the perpetrator truly a key issue in the case?

• Can a DNA test conclusively establish the innocence of the defendant?

''We're not rolling over just because it's a DNA case,'' said Krischer, of Palm Beach County. ``They still have to meet the legal threshold set by law.''

Herald staff writer Wanda DeMarzo contributed to this report.