Lisa Gonzales, 55, a San Francisco woman, has been convicted of second‑degree murder for the 2018 killing and dismemberment of her 61‑year‑old roommate, Margaret Mamer, whose remains she hid in a blue storage container in the basement of their Mission District apartment building. A jury found her guilty on April 1, 2026, and the San Francisco District Attorney announced that the jury also found true the allegation that she personally used a knife in the murder.
What happened in 2018
Mamer was reported missing on June 1, 2018, after friends noticed she had not been in touch for more than a week and were concerned about rising tension between her and her roommate, Gonzales. The next day, another person contacted police saying a murder likely occurred at 255 W. 14th Street, claiming Gonzales had killed someone, dismembered the body, and tried to conceal it in a container in the building’s basement.
When officers arrived, Gonzales said Mamer had once lived there but had moved to Eureka on or about May 15 and that she had helped her move out. Yet in the building’s storage area, police found a blue container holding badly decomposed human remains later identified as Mamer. The body was covered with maggots, indicating it had been there for weeks.
The killing and dismemberment
An autopsy showed that Mamer suffered multiple sharp‑force injuries to her face and skull, as well as stab wounds to her chest. After she died, portions of her forearms and legs were sawed off and her body was cut in half. A third roommate told police that Gonzales had given Mamer a 30‑day move‑out notice in mid‑April 2018 but became frustrated when Mamer did not comply.
Coworkers later told investigators that Gonzales had complained about Mamer’s refusal to leave and said she would handle the eviction “her way” rather than through legal channels. On the day of the killing, the third roommate reported hearing sawing noises from the bathroom for hours, noticing a strong metallic smell, and later finding the bathroom door open, the apartment smelling of vinegar and bleach, and her missing blue clothes container gone. Gonzales told her Mamer had left “but not the way she wanted to.”
Legal outcome and sentence exposure
San Francisco District Attorney Brooke Jenkins called the case “one of the most gruesome crimes our city has experienced in recent history.” Gonzales now faces a sentence of 16 years to life in prison on the second‑degree‑murder conviction, though the specific sentencing date has not yet been set.
