The 64-year-old former trash collector was convicted of 10 counts of first-degree murder and one count of attempted murder last week following a two-month trial.
Prosecutors said Franklin targeted vulnerable young black women in South Los Angeles during the crack cocaine epidemic. The 10 victims, including 15-year-old Princess Berthomieux, were fatally shot or strangled and dumped in alleys. Some were prostitutes and most had traces of cocaine in their systems.
The killings from 1985 to 2007 were dubbed the work of the "Grim Sleeper" because of an apparent 14-year gap after one woman survived a gunshot to the chest in 1988.
Deputy District Attorney Beth Silverman presented evidence of similar killings connected to Franklin Thursday that expands the range of rage and includes a slaying from 2000, during the serial killer's so-called "sleep."
She presented a photo display never seen before. Besides the 10 murder victims for which Lonnie Franklin has already been convicted, six more faces were added. Silverman says the deaths or disappearances are linked to Franklin by guns and photographs found in his home.
Silverman told the jury that Franklin's reign of terror began in 1974 with a gang rape in Germany when he was in the Army. That was followed by the murder of Debra Jackson in 1985, which was initially thought to be Franklin's first murder. But now, Silverman says, there's evidence he killed Sharon Dismuke a year and a half earlier with the same gun used to kill victim No. 10 Janecia Peters in 2007.
"Three different firearms were utilized by the defendant over the course of these crimes over the years," Silverman said.
Evidence of the additional killings came to light after Franklin was indicted. Silverman said she chose not to charge Franklin with those killings because it would have delayed the case that took nearly six years to bring to trial.
On Thursday, jurors were told to consider the enormity and viciousness of Franklin's crimes.
Henrietta Wright left behind her then 4-year-old daughter, Rochell Wright Johnson, who says she's still scarred to this day.
"I don't like to speak to people I don't know, I don't. I just keep forward because you don't know who they are," Johnson testified.
Alicia Monique Alexander was 18 years old when she was killed. Her brother, Donnell, said their family was like "The Brady Brunch." Her parents said she was pursuing gymnastics, figure skating, ballet and horseback riding.
When her parents learned of her death, Alexander's father, Porter, testified that his wife collapsed.
"It got to a point where I didn't want to be here," Alexander's mother told jurors.
Mary Lowe was killed and dumped in an alley. Her sister says she was a "Soul Train" dancer.
The penalty phase of the trial is expected to last several weeks, at which point the jury will decide whether Franklin will be sentenced to death or life in prison without the possibility of parole.
The Associated Press contributed to this report