San Francisco woman convicted of 2018 murder, dismemberment of roommate, DA says

SAN FRANCISCO (KGO) — A San Francisco jury has convicted 55-year-old Lisa Gonzales of second-degree murder for the 2018 killing and dismemberment of her roommate, Margaret Mamer.

District Attorney Brooke Jenkins, who worked on the case during her time in the homicide unit, said the verdict brings long-delayed justice.

“This is one of the most gruesome crimes our city has experienced in recent history,” Jenkins said. “I remember putting in the grand jury proceedings and having to call the witnesses to the stand to testify about what they heard and what they saw. And this was very gruesome. It was very difficult to get through that testimony.”

Gonzales was also found to have personally used a knife during the murder.

Mamer was reported missing on June 1, 2018, after friends became concerned when they hadn’t heard from her and knew tensions were escalating between her and Gonzales, according to the DA’s office. The next day, another person went to police reporting that a murder may have occurred inside the roommates’ Mission District apartment on the 200 block of 14th Street.

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When officers arrived, Gonzales invited them inside and told them Mamer had moved to Eureka weeks earlier. During a search of the building’s storage area, police found a blue plastic container holding human remains later identified as Mamer’s.

According to testimony, a third roommate told investigators she had heard sawing noises coming from the bathroom for hours and noticed strong smells of vinegar and bleach throughout the apartment. She also reported seeing a hacksaw under the sink and noticing that her own blue storage container was missing.

When she asked where Mamer had gone, Gonzales replied that she had left “but not the way she wanted to.”

Coworkers testified that Gonzales had complained for weeks about wanting Mamer out of the apartment. When offered legal ways to evict her, Gonzales reportedly responded, “No thanks. I’ll do it my way.”

An autopsy determined Mamer died from multiple sharpforce injuries to her head, face, skull and chest.

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Prosecutors said Gonzales dismembered the body in an attempt to conceal the killing, and that the remains were left in the storage unit for weeks before being discovered.

“Sadly, not only was she dismembered, but it took a number of weeks to locate her. And so, the body had experienced significant decay by then,” Jenkins said.

The nearly eight-year delay between the crime and the trial complicated the case.

“The best advantage that they can gain is to delay so that memories fade, so that we lose contact with witnesses,” Jenkins said.

Jenkins also explained that a first-degree murder charge with pre-meditation was hard to prove in court.

“When, sadly, the only other person involved in this — if you call it dispute or situation — cannot testify, is no longer alive,” Jenkins said.

Gonzales remains in custody and faces 16 years to life in prison. A sentencing date will be set at a hearing later this month.