Nathan Burris told a Contra Costa County jury Wednesday that they should "flip a coin" to decide whether to sentence him to death for killing his former girlfriend and her friend on the Richmond-San Rafael Bridge.

The 49-year-old Richmond man, who was convicted last week of murder charges with special circumstances for fatally shooting 51-year-old Deborah Ross and Ersie "Chuck" Everette, 58, during rush hour at the bridge's toll plaza on Aug. 11, 2009, took the witness stand in the penalty phase of his trial.

Burris reiterated his stance Wednesday that it doesn't matter to him which penalty he receives, although he told jurors that he believes his victims' families prefer that he get a life sentence without the possibility of parole.

"Whichever one, I'm content with it," he testified today, often smiling and smirking as he addressed the jury.

Several members of the victims' families heard Burris testify in court as they have throughout the trial.

Burris also told the court for the first time Wednesday that he had committed "several armed robberies" in San Francisco in 1995. He described one robbery in which he claimed he had robbed a Walgreen's pharmacy of tens of thousands of dollars in cash at gunpoint.

Contra Costa County Judge John W. Kennedy will consider whether that confession constitutes circumstances in aggravation that could weigh on the jury's decision during this phase of the trial.

During the guilt phase of the trial over the past few weeks, Burris told the jury that he feels no remorse for killing his former girlfriend of more than a decade, who worked at the toll plaza, and her friend, Everette, a Golden Gate Transit bus driver from San Leandro.

He testified that his anger over suspicions that Ross had cheated on him with Everette spurred him to shoot and kill Everette as he sat in a parked pickup truck at the toll plaza, next firing on Ross in the toll booth where she worked.

Closing arguments are now set for Thursday morning.