Lisa Gonzales was found guilty for the murder and dismemberment of her former roommate, Margaret Mamer. Photo on July 18, 2018 by Charlotte Silver.

A San Francisco jury convicted Lisa Gonzales, 55, for the grisly 2018 murder and dismemberment of her roommate Margaret Mamer in their Mission District home, the district attorney’s office announced today.

It was a “deeply disturbing and heartbreaking case,” as Assistant District Attorney Melissa Demetral put it, and one that shook the neighborhood

Gonzales repeatedly demanded Mamer, 61, move out from their residence on the 200 block of 14th Street, according to court records. Gonzales was the master tenant.

When coworkers told Gonzales “various ways she could legally evict the victim, Ms. Gonzales responded with, ‘No thanks, I’ll do it my way,’” the DA’s office wrote. 

Mamer, who had not been seen for weeks, was reported missing on June 1, 2018. The details that follow are disturbing.

The following day, police received a report that Gonzales had murdered someone and attempted to hide the dismembered body in a container in her basement, the DA’s office wrote. Police responded immediately. Gonzales invited the officers inside, and told them she lived with only a different roommate. Mamer, she said, had moved out in May 2018. 

But police uncovered a blue container in her storage area, which had a “pungent” odor, court records read. Within was a plastic bag covered in maggots. A “viscous” liquid bubbled out. After obtaining a warrant, officers found Mamer’s severed arms and legs and intact head and torso. 

The decomposing remains of Margaret Mamer were discovered by police in the basement of 255 14th St. Photo by Abraham Rodriguez.

On May 15, 2018, Gonzales told her other roommate not to enter their bathroom, the roommate told police. Later that day, the roommate noticed a “rotten eggs” smell in the bathroom, court records read. She heard “sawing noises” coming from the bathroom for the next four hours. 

Gonzales was still in the bathroom the following morning. When the roommate returned from work the next day the apartment smelled like “vinegar and bleach” instead, the DA’s office wrote. A blue container she kept her dirty clothes in had vanished. There was a hacksaw under the sink in the laundry room. 

She reported asking Gonzales where Mamer had gone.

“She left,” Gonzales replied, “but not the way she wanted to.”

Police later found Mamer’s blood splattered throughout the bathroom. She died of “multiple sharp force injuries to her head and heart,”an autopsy revealed. Mamer’s body had sat in her roommate’s container for at least two weeks.

“The jury’s verdict delivers justice to the victim’s family and friends who continue to grieve and are still deeply impacted by this heinous murder,” District Attorney Brooke Jenkins wrote in a statement.

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Abigail is a staff reporter at Mission Local covering criminal justice and public health. She got her bachelor's and master's from Stanford University and has received awards for investigative reporting and public service journalism.

Abigail now lives in San Francisco with her cat, Sally Carrera, but she'll always be a New Yorker. (Yes, the shelter named the cat after the Porsche from the animated movie Cars.)

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7 Comments

  1. I’m always baffled by cases where the murderers know full well they will never get away with it, and yet do it anyway.

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    1. Presumably it was not premeditated, but rather the result of an argument that got out of hand. The article doesn’t say but in that case it would be second degree murder.

      One downside of rent control can be tenants staying in homes where they are no longer welcome, with the relationship then going downhill.

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      1. The tenant in question had been there less than a year, so blaming rent control for this is a little ridiculous. Also, the murderous roommate had multiple legal options for removing her tenant. She chose not to use them. Trying to turn this into a rent-control screed is… definitely a choice.

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