Within minutes, the surprise move by Lewis, 23, and defense attorneys Michael Coard and Bernard L. Siegel refocused what was predicted to be a three-week trial - prosecutors had to prove a murder and six armed robberies - into a much shorter proceeding about life or death.

Lewis' guilty pleas to murder, robbery, possession of a weapon used in the crimes, and assault occurred at the trial's start, with 12 jurors and four alternates in the box, a courtroom packed with Cassidy's and Lewis' families, and a phalanx of police officers and brass lining the walls and aisles.

Spectators leaned forward as if to make sure they had heard Lewis correctly. Judy Cassidy, the officer's widow, began weeping and leaning against her daughters.

On the opposite side of the room, Lewis' mother, Lynn M. Dyches, a Philadelphia correctional officer, also started sobbing. Lewis' siblings and other relatives comforted her.

But the flash interpretation of events as a plea bargain to escape the death penalty was quickly doused. There was no plea agreement.

For months, court watchers and the law enforcement community had pondered what possible defense could be mounted for Lewis. The Cassidy murder is on a Dunkin' Donuts security-camera video, and Lewis confessed.

Yesterday's answer came in what appeared to be an unusual defense gambit to undercut weeks of emotional testimony about six robberies and frightened victims, and instead concentrate on what was always the case's central issue: life in prison or death.

After the guilty pleas, Assistant District Attorneys Jennifer Selber and Edward Cameron began presenting witnesses to prove that the death of Cassidy, 54, in the Oct. 31, 2007, robbery of the North Philadelphia doughnut shop was a premeditated first-degree murder and not a second-degree murder committed during another felony.

Under Pennsylvania law, if the jury finds Lewis guilty of first-degree murder, it will have to decide if he should be put to death or sentenced to life in prison without chance of parole. Second-degree murder carries an automatic sentence of life without parole.

The prosecutors presented five witnesses yesterday who identified Lewis as the gunman in two of six robberies he admitted.

Prosecutors say Lewis began his robberies on Sept. 18, 2007, at the Dunkin' Donuts at 6620 N. Broad St. in West Oak Lane. The string ended about six weeks later, in the same Dunkin' Donuts, when Cassidy walked through the door and Lewis shot the 25-year officer once in the head. Cassidy died the next day.

The trial resumes this morning at the Criminal Justice Center in Center City.

Yesterday, Lewis himself remained calm and outwardly unaffected by the emotion roiling about him. A large man with a baby face accentuated by oversize black-framed glasses, Lewis made clear to the judge that the defense decisions had been made by him and his lawyers - not imposed on him by lawyers.

Court observers said the tactic could purchase some good will for Lewis for accepting responsibility and sparing commonwealth prosecutors the expense - and the families and witnesses the anguish - of an arduous trial.

If so, prosecutor Selber immediately worked to counter that impact, telling the jury in her opening statement that Lewis "finally pleaded guilty" because he was "buried under a mountain of evidence."

"He is only taking responsibility for the parts that he has to," Selber said.

Selber said the video of Cassidy's death would prove that Lewis had made a deliberate decision to kill the officer, shooting him in the head after taking several steps and raising his gun from a distance of about three feet.

"He didn't just happen to die in the commission of a robbery," Selber said.

Selber said she would show that Lewis' robberies had become increasingly threatening. "He was flirting with murder."

"You will see the evolution of a criminal from robbery to murder," Selber told the jury.

Defense attorney Coard urged the jurors to follow the law, as they had promised Common Pleas Court Judge Jeffrey P. Minehart they would.

Coard described Cassidy as a "hero who died at the hand of John Lewis."

"You'd be hard-pressed to find a case that brings more sadness and more sympathy," Coard added.

But he told the jury that the evidence would not prove Lewis had planned and premeditated the killing of a police officer. "It involved a panicky reaction during a robbery that led to a tragic death of a heroic police officer."

Lewis admitted the shooting after he was arrested in Florida on Nov. 6, 2007, three days after he was publicly identified as a suspect. He had fled to Florida on a Greyhound bus from Wilmington.

After wandering the streets of Miami for a few days, Lewis checked into a homeless shelter under an alias. But his evasive and nervous behavior and his photo on a news broadcast led a shelter employee to call police, and he was arrested.

That night, as Miami police led him from headquarters to a courthouse jail cell, Lewis, a high school dropout with a history of drug arrests, was besieged by reporters and TV crews.

He told reporters he had confessed to shooting Cassidy, then faced the cameras and said: "I apologize to his family. I never meant anything to happen like this."