One suspect was charged and a second was being sought Sunday in the killing of a Philadelphia police officer who was shot with an assault rifle while responding to a bank robbery, police said.

Levon Warner, 38, was charged with murder, robbery, conspiracy and related offenses, Deputy Commissioner William Blackburn said at a news conference Sunday. A second man, Eric Floyd, 33, believed to have escaped from a halfway house in Berks County, is also wanted on a homicide charge. A third man, Howard Cain, 33, was shot to death by police.

Sgt. Stephen Liczbinski, a 12-year veteran who would have turned 40 on Tuesday, was responding to the robbery of a bank inside a grocery store around 11:30 a.m. Saturday. The suspects fled and opened fire after Liczbinski confronted them a short distance away, authorities said.

"The sergeant didn't have a chance," Blackburn said, adding that Liczbinski was shot at least five times.

Police also recovered two vehicles, one of which contained a high-powered assault rifle with 25 live rounds. They also found other weapons, $38,000 in cash and several sets of Muslim clothing that the suspects apparently wore as disguises, police said.

Shortly after the robbery, Warner reported his van stolen, Blackburn said. But police later determined he was involved in the crime and that his vehicle had been used as a getaway car.

Blackburn warned that the wanted suspect, Floyd, should be considered "extremely armed and dangerous."

"The entire Philadelphia Police Department is working nonstop," he said. "We're asking him to turn himself in."

Mayor Michael Nutter declared a 30-day period of mourning for the slain officer and requested that all flags in the city be lowered to half-staff for that period.

On Sunday night, dozens attended a candlelight vigil for Liczbinski in the Port Richmond neighborhood where the officer was slain.

Liczbinski was married with two sons and a daughter.

Funeral arrangements were announced Sunday. A viewing will be held for Liczbinski on Thursday night and Friday morning at the Givnish Funeral Home on Academy Road in northeast Philadelphia. A funeral mass will be held at noon Friday at the Cathedral Basilica of Saints Peter and Paul.

On Saturday, blue-shirted officers, some wearing white motorcycle helmets, lined both sides of a black hearse and saluted as the slain officer's body, draped with an American flag, was put inside at the hospital. Police motorcycles, some bearing black- and blue-striped flags, then escorted the hearse away.

Liczbinski's killing came only a few days after Police Commissioner Charles Ramsey announced a major reorganization of the police department's command structure and the addition of nearly 250 officers on street patrols as part of a strategy to reduce crime.

The shooting came about six months after the last death of a Philadelphia officer in the line of duty. Officer Chuck Cassidy, 54, also a father of three, was killed during the botched robbery of a doughnut shop on Oct. 31; the alleged gunman is awaiting trial.

Nearly two years ago, in May 2006, Officer Gary Skerski was fatally shot in the neck when a man robbing a bar fired a shotgun out the back door. The killer, Solomon Montgomery, pleaded guilty to first-degree murder and was sentenced to life in prison.