Olga Rutterschmidt, 75, was convicted of first-degree murder and conspiracy to murder for financial gain in the death of Paul Vados, 73. Last week, she was convicted of murder and conspiracy in the death of Kenneth McDavid, 50.
The jury returned to deliberations Monday after bringing in an alternate to replace a juror who had to leave on a trip. Co-defendant Helen Golay, 77, was convicted of both murders and conspiracy last week.
Defense attorney Michael Sklar said he will begin working on a motion for a new trial, but had no other comment.
Jurors had said that they were deadlocked on the last two counts against Rutterschmidt, but were ordered to start deliberations over on those counts because of the new member. The verdicts came after about an hour of talks.
Prosecutors said the two women collected $2.8 million before their scheme was uncovered during the investigation into the 2005 death of McDavid in what initially looked like a hit-and-run accident. An investigator overheard another detective discussing the 1999 death of Vados in very similar circumstances.
From the start, the defendants' advanced ages kept the case in the headlines, drawing comparisons to the play and film "Arsenic and Old Lace," the Los Angeles Times reported. The killings came to be known as the Black Widow murders.
The women were accused of recruiting the men from among Hollywood's homeless and giving them lodging and food while taking out numerous insurance policies on them.
The convictions carry life prison terms without possibility of parole for both women. Prosecutors chose to not seek the death penalty.