The grand jury indictment charged Alberd Tersargsyan with killing Khachik Safaryan and his 8-year-old daughter Lusine in their Hollywood apartment on Dec. 11, 2008.
Nearly two years later, the wife and mother, Karine Hokobyan, was found shot to death in her car. Prosecutors believe Tersargsyan was obsessed with the woman.
In March 2010, prosecutors believe Tersargyan shot and killed Julie Kates in a sniper-style shooting because he thought a friend of Kates stole a DVD from him.
Prosecutors have not yet decided whether to seek the death penalty against the 65-year-old defendant, who was charged last year and had been awaiting a hearing to determine if there was enough evidence to proceed to trial.
The indictment includes a new special circumstance allegation - murder of a witness - involving the 8-year-old girl, along with the special circumstance allegations of lying in wait and multiple murders that Tersargsyan was already facing.
Tersargsyan, who is jailed without bail, is due back at the downtown Los Angeles courthouse Oct. 17 for a pretrial hearing.
City News Service contributed to this report.