The hunt for the killer of Officer Chuck Cassidy took on new urgency last night after investigators said the prime suspect boarded a bus this weekend for Miami and police recovered the dead officer's stolen gun in Hunting Park.

Law enforcement officials said they believe John Lewis, 21, boarded a bus for Florida on Saturday night, only hours after police received a tip identifying him as the triggerman in Wednesday's slaying of Cassidy .

Florida officials have been alerted, and homicide detectives were to fly to Miami this morning. Police Commissioner Sylvester M. Johnson said police have asked the FBI to add Lewis to its "Ten Most Wanted" list.

Law enforcement officials said a relative, called in for questioning, admitted purchasing a bus ticket for Lewis on Saturday. They believe Lewis would have arrived in Florida late Sunday.

The rapidly expanding investigation leaped forward yesterday afternoon when police recovered two handguns that they say link Lewis to the murder.

One was the officer's 9mm Glock semiautomatic, stolen immediately after he was gunned down. The second firearm may be the murder weapon. Analysts were conducting a ballistics test on it last night.

Both handguns were taken from a house in the 3800 block of North Franklin Street, the residence of an associate of Lewis'.

The recovery of two handguns added weight to the evidence against Lewis. Johnson said there was "no doubt" that investigators were looking for the right man.

Before he fled, Lewis told family members he would not surrender, according to a federal warrant issued for his arrest early Sunday. "Lewis expressed a desire not to be captured," the warrant stated.

The affidavit also stated that Lewis confessed to his family.

Cassidy , 54, was shot Wednesday morning after he interrupted an armed robbery at a Dunkin' Donuts in West Oak Lane. Police said the surprised assailant wheeled and shot Cassidy in the head from five feet away.

A law enforcement source said last night that the second handgun recovered yesterday was not the firearm reported missing by Lewis' mother, Lynn Dyches, a corrections officer in the Philadelphia Prison System. Police initially suspected that her gun might have been used in the murder.

Reached by telephone last night, Dyches complained that the police and the media were distorting the image of her son. "I don't want no more negative stuff out there," she said. "Everything the news media is playing out now is a lie. They say he had a record, and all he was doing was smoking marijuana, for which he did community service. Everything they're putting on TV is a lie. "

The introduction of perhaps a third handgun into the equation raised the prospect that the suspect might still be armed.

"Even though there's two weapons recovered, we're saying this man is still considered very dangerous," said Johnson.

Lewis is described as 6 feet tall and weighing 270 pounds, a black man with a medium complexion, short cropped hair, and scruffy facial hair. From a surveillance video of the killing, he appears to have a lumbering gait.

Police said Lewis has two tattoos: the initials "HP," for Hunting Park, on his right hand, and "NP," for North Philly, on his left. The suspect does not have a spider-web tattoo, as authorities initially announced.

"We know exactly who we're looking for, which is a positive thing," Johnson said at an impromptu briefing outside Police Headquarters. "Now, our next step is to apprehend him. "

Authorities urged Lewis, an Olney High School dropout who is known to frequent North Philadelphia and the Lower Northeast, and who also goes by the name "Jordan Lewis" and sometimes uses "Jordan" as his last name, to surrender.

"We're appealing to this man to turn himself in at the earliest possible time," Homicide Inspector Joseph Mooney said. "It's better for him, it's better for everyone else in the public and police officers out there. "