Family of woman killed by deputy sues: Yanira Serrano, 18, who suffered from schizophrenia, shot near Half Moon Bay

San Mateo County District Attorney Steve Wagstaffe declined to file criminal charges in the case last month, writing in a letter to Sheriff Greg Munks that Serrano ran screaming toward Trieu holding a 10-and-a-half-inch kitchen knife over her head.

The complaint, however, disputes that version of events, calling the knife a “paring knife” and said because Serrano was obese and disabled with an atrophied leg, “she could not meaningfully run and limped badly.”

Trieu first responded to the Moonridge housing complex on Miramontes Point Road at about 9:30 p.m. on June 3 after Serrano’s brother, Lorenzo Serrano, called 911 to report that his sister had refused to take her medication and was yelling at his parents but was not violent.

According to the complaint, Lorenzo Serrano told the 911 dispatcher, “this is not really an emergency, I’m calling because my sister has schizophrenia” and specifically requested a medical response.

Trieu was the first to arrive at the home after two other deputies got lost on their way, according to the complaint. When he got out of his patrol car, the family was inside.

The complaint criticizes Trieu for not waiting for other deputies to arrive before getting out of his car, arguing that standard police training required him to wait, that there was no immediate danger and that his arrival could contribute to the deterioration of Yanira Serrano’s state of mind.

She came out of the home holding a knife that she had been using to cut fruit, according to the complaint. She “hobbled” toward him and he moved away, but when she came within 10 feet of him, he shot her once in the chest.

Wagstaffe’s letter disputes this interpretation of events.

She “ran towards the deputy, screaming in what can be described as a primal, incoherent and garbled tone,” Wagstaffe wrote.

Trieu repeatedly yelled at her to stop and retreated into the street, looking for his partner who hadn’t arrived.

Trieu did not have time to unholster his Taser before Yanira would reach him as he ran backwards and she was wearing a large sweater that might have prevented the Taser from working, so he fired his gun, according to Wagstaffe.

The shooting happened about 30 seconds after Trieu arrived at the home. He called for medical aid but she died within minutes.

Wagstaffe said witnesses corroborated Trieu’s version of events, describing Yanira Serrano as swearing in Spanish as she moved toward the deputy and saying, “You are not going to take me! You are not going to take me!”

The district attorney concluded that Trieu’s life was legitimately in danger and despite his knowledge of her mental illness, he had no non-lethal way of preventing her attack.

Yanira Serrano’s parents and brother watched the shooting and, according to the complaint, Trieu prohibited them from comforting her as she died, pointing his handgun at them and telling them to stay away.

The family is seeking unspecified damages from Trieu and the county for excessive force and unreasonable seizure and a substantive due process violation.