Frank Tepper's fate was sealed months ago, when a Common Pleas Court jury convicted the former Philadelphia police officer of first-degree murder for shooting a 21-year-old neighbor outside his Port Richmond home in 2009.

Another jury was handed a more complex set of questions on Monday: Was Tepper's killing of Billy Panas part of a pattern of predictable rogue behavior that went unchecked during his 16 years as a police officer? If so, should the city be held accountable? Or was Tepper a "drunken idiot" acting on his own?

Opening a federal civil rights trial against Tepper and the city that could last a week, a lawyer for Panas' family told jurors he would peel back the curtain on consistent "willful blindness" by Tepper's colleagues and supervisors toward conduct that ultimately cost Panas his life.

Tepper kept his badge despite racking up 35 citations in the department's Internal Affairs files, and complaints about reckless or possibly criminal behavior, lawyer James Binns said.

Among them, according to Binns, were claims that Tepper aimed his gun at a 10-year-old boy whose dribbling a ball on a playground kept Tepper awake, that he emptied a can of department-issued pepper spray at teens he suspected had bullied his son, and that he pistol-whipped a motorist he believed had been talking to his fiancee.

Time and again, Binns said, an alcohol-soaked Tepper flaunted his badge and his title, as on the night he shot Panas. And nearly every time, he eluded discipline or action.

"Basically, Frank Tepper was a bully, someone who never should have been a police officer, never should have worn a badge, never worn a uniform," Binns told jurors as Panas' parents, Bill and Karen, sat in the courtroom's front row, wiping away tears.

"The City of Philadelphia in fact caused the murder of Billy Panas by allowing [Tepper], all those years, to get away with murder, so to speak. The only thing he didn't do on all those other occasions is pull the trigger."

A lawyer for the city called the death "tragic" and Tepper a "drunken idiot" but said his actions were his own.

The lawyer, Armando Brigandi, conceded Tepper's checkered record as a police officer but said he had had no "significant" complaints for nearly seven years before the November 2009 shooting.

And that night, Brigandi said, Tepper was off-duty and drunk when he grabbed his own gun in a bid to disperse a group of young men arguing in front of his house, where Tepper's daughter was having a baby shower.

When Tepper waved the gun and said he was a police officer, Panas told the others, "He won't shoot anybody." Tepper aimed at his chest and fired.

Tepper was not acting in his role as an officer, Brigandi said, so the city is not liable for his actions.

"The only reason Frank Tepper shot Billy Panas," he said, "was because he was drunk and he was embarrassed and because someone dared him to shoot."

The trial could include testimony or statements from dozens of officers, including inspectors or other ranking officials.

Missing from the courtroom was Tepper, who was sentenced to life in prison without parole.

Tepper essentially walked away from the civil case. He has no lawyer representing him, and U.S. District Judge Legrome D. Davis told the panel of five women and three men that Tepper "has chosen not to be here."

They are expected to see a videotaped deposition in which Tepper chose not to answer questions, invoking his Fifth Amendment right against self-incrimination.

Binns said he planned to call a pathologist who would describe the pain and suffering Panas felt on the night he was shot. An economist will testify about how much Panas, a budding barber, could have earned over a lifetime.

The Panases' suit seeks as much as $62 million in damages, although the biggest portion, $50 million, is punitive damages, which the city would not have to pay.

Contact John P. Martin at 215-925-2649, at jmartin@phillynews.com or @JPMartinInky on Twitter.