SAN FRANCISCO (CBS SF) — The mother of a 28-year-old man fatally shot by San Francisco police in a city park two years ago testified in federal court Monday that she feels the loss every day.

Elvira Nieto came to the stand in U.S. District Court in San Francisco in the trial of a civil lawsuit she and her husband filed against four officers who shot and killed their son, Alejandro “Alex” Nieto, in Bernal Heights Park on March 21, 2014.

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When asked by the family’s attorney, Adante Pointer, how the loss affected her, she answered, “It affected me a lot.”

“Even now, I hear his voice,” she said, speaking through a translator. “My heart is not accepting it, that he is not here.”

The mother said her husband, Refugio Nieto, is also greatly affected.

“Every day, he goes for a walk over there (in the park). Sometimes he goes twice a day,” she told the jury.

The parents’ lawsuit is based on claims of wrongful death, unconstitutional excessive use of force, and deprivation of the right to a familial relationship with their son.

Nieto, who was carrying a Taser stun gun in his holster, had eaten a burrito at the park and was on his way to his job as a security guard at a local nightclub when he was shot shortly after 7 p.m. in a barrage of 59 bullets fired by the officers in 30 seconds.

The officers were responding to a dog walker’s report of a man with a gun. They testified last week that they believed Nieto had a real gun and that he was pointing it at them. Three of the four officers said they saw red laser sights on the device.

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A second dog walker, Antonio Theodore, brought to the stand by Pointer last week testified that Nieto kept his hands in his pockets during the encounter and that he never saw Nieto point anything at the officers.

The four officers are Lt. Jason Sawyer, who was a sergeant at the time, and Officers Richard Schiff, Nathan Chew and Roger Morse.

Elvira Nieto also testified Monday that after Friday’s trial session, the family and supporters went to Bernal Heights Park to commemorate what would have been Nieto’s 30th birthday.

“It was my son’s birthday. We brought flowers, a balloon and cake. Quite a few people came to keep us company,” she said.

She described a family trip with her son to Mexico and a family Christmas celebration, illustrated by photos projected on a screen by Pointer.

The plaintiffs plan to complete presenting their evidence Tuesday morning, after which City Attorney’s Office lawyers defending the officers will present four witnesses.

The case is expected to go to the eight-member jury in the court of U.S. Magistrate Judge Nathanael Cousins later this week.

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