Brandishing a list of nearly 500 violent repeat offenders, Allegheny County District Attorney Stephen A. Zappala Jr. said yesterday that he supports a plan to keep them behind bars longer.

Gov. Ed Rendell announced Sunday that he will push for a bill that compels prisoners who have committed multiple violent crimes to serve out their maximum prison sentences. The proposal would make such prisoners ineligible for parole before the end of their sentence, but they would remain under parole board supervision for up to five years after their release.

Mr. Zappala said a detective and two paralegals in his office have tracked 487 people since the summer of 2006 who were arrested while on bond, parole or probation from a violent or felony drug case.

"I know these people are dangerous," he said. "I just think the community's safer with these guys off the street. They're going to re-offend."

Bob Caton, spokesman for House Speaker nominee Rep. Keith McCall, D-Carbon, said legislators will start moving on a bill later this month.

"We support the governor's proposal, and the idea of keeping more repeat violent felons behind bars is a good one," Mr. Caton wrote in an e-mail.

Veteran Allegheny County criminal division Judge Jeffrey A. Manning was skeptical of the plan, saying it was an overreaction to the headline-grabbing murder of a Philadelphia police officer in September.

"As the old law school saying goes: Bad cases make bad laws," he said.

Judge Manning serves on the state's 11-member Sentencing Commission, which was tasked last fall with reforming parole guidelines. The governor's new proposal, he said, would undermine that effort and "change the entire sentencing scheme in Pennsylvania."

Judge Manning said he favors giving an extended maximum sentence to violent criminals -- say, five to 20 years instead of five to 10 -- to make sure they are under parole supervision for longer.

"Except in the most severe cases, no one goes to Devil's Island; no one goes away forever," he said. "I much prefer someone be placed on parole, so they are supervised upon their release and properly reintegrated."

William DiMascio, executive director of the Pennsylvania Prison Society, also emphasized effective reintegration. He said teaching inmates skills that will help them land good jobs would be a more effective strategy than longer sentences, which just lead to hardened criminals more likely to return to their old ways.

"[Mr. Rendell is] relying on the failed strategies of the past that have led to all these problems," he said, adding that longer sentences won't help a prison system already bursting at the seams.

The plan's proponents see it as a way to prevent the most serious of crimes. According to Chuck Ardo, Mr. Rendell's spokesman, the mandatory maximums would apply to people convicted multiple times of third-degree murder, voluntary manslaughter, aggravated assault, rape and robbery -- or one violent crime and one gun offense.

Mr. Rendell's proposal came after he issued a moratorium on all parole in the fall following the killing of a Philadelphia police officer by a parolee. In announcing his plan Sunday, Mr. Rendell cited two other Philadelphia-area cases involving deaths caused by prisoners on parole.

Mr. Zappala, though supportive of the plan, was miffed at the governor's focus on Philadelphia, where Mr. Rendell served as mayor.

The district attorney asked why Pittsburgh's spike in homicides last year or the November killing of FBI Special Agent Samuel Hicks during a drug raid in Indiana Township didn't warrant gubernatorial attention.

"From a criminal justice perspective, he hasn't done anything for Western Pennsylvania," Mr. Zappala said. "He reacts to things that happen in Philadelphia. We pay a lot of money to Harrisburg in taxes. We should get the benefit."

Mr. Zappala said his 2006 request for $1.5 million in state funding for a special gun unit in the district attorney's office went nowhere. The unit, which targets violent drug rings across jurisdictions in the county, is currently funded by assets the county seizes from criminals.

In addition to keeping repeat offenders locked up for longer, he said, the state should pony up more funds for law enforcement.

"I think it's a good thing," Mr. Zappala said of the longer sentences, "as long as it's not just rhetorical."