NEW YORK - Both sides in the murder trial of Lillo Brancato agree on one thing: The once promising "Sopranos" actor was a junkie who officially hit bottom on Dec. 10, 2005, the night an off-duty police officer was killed during a burglary in the Bronx.

In opening statements Monday, jurors were asked to decide whether Brancato was a partner in crime with a man already convicted of shooting and killing the officer or merely an innocent bystander.

Brancato -- who got his start in the film "A Bronx Tale" and later appeared in "The Sopranos" -- was led into the Bronx courtroom in a neatly tailored grey suit and handcuffs.

Prosecutors say Brancato and Steven Armento tried to break into the Bronx apartment to swipe prescription drugs after a night of drinking at a strip club in nearby Yonkers.

"In their effort to get drugs to satisfy their own desires, they took the life of a New York City police officer," said assistant district attorney Theresa Gottlieb.

Brancato's lawyer, Joseph Tacopina, told the jury his client was an addict who "ruined his life" with drugs and was "clearly strung out" at the time of the slaying.

But he argued that the true culprit was Armento, who was convicted of first-degree murder on Oct. 30 and has been sentenced to life in prison without parole.

"Lillo was there to satisfy his addiction but he wasn't there to do violence," Tacopina said. "Lillo didn't try to hurt a single person that night."

Brancato, 32, made his debut in 1993 in "A Bronx Tale" opposite Robert De Niro. He has appeared in more than a dozen other movies and played a doomed aspiring mobster in HBO's "Sopranos."

By law, prosecutors were allowed to charge Brancato with second-degree murder in the death of Officer Daniel Enchautegui because they say the killing occurred while both he and the actual shooter were committing a felony -- a break-in. If convicted of murder and burglary, he faces a possible life term.

Enchautegui, who lived next door to the apartment where prosecutors say Brancato and Armento were trying to steal drugs, grabbed his gun and came out to investigate. Armento shot the 28-year-old officer in the heart. Enchautegui fired back, wounding both men.

The case could turn on whether the jury believes Brancato knew Armento was carrying a loaded revolver. Prosecutors say Brancato's drug dealer will testify that Armento had pulled the weapon on the dealer earlier in the night in front of Brancato.

But Tacopina branded the drug dealer a liar angling for leniency in his own legal troubles. Brancato was startled that his friend opened fire, and didn't know the man firing back was a patrolman, he said.

A detective who was one of the first to respond to the scene testified Monday that when he asked a bloodied Brancato who shot him, the actor responded, "That bitch." Moments later, he said it was a "bald guy" -- an apparent reference to the balding officer.