Alejandro "Alex" Nieto was a man who was shot and killed by four San Francisco Police Department officers on March 21, 2014, in the Bernal Heights neighborhood of San Francisco, California. Nieto was a bouncer at a local nightclub, and the shooting took place before he was to start work that evening. A couple called 911 when they saw him sitting on a bench and saw Nieto's taser. Nieto was wearing a taser, and the police officers alleged that Nieto pointed the taser at them. The responding police officers also said they believed that the taser was a firearm.

The San Francisco County District Attorney's Office declined to file criminal charges against the four officers involved in the shooting. Nieto's family filed a federal civil rights lawsuit, alleging wrongful death. In March 2016, a jury cleared the four officers of all charges.

Nieto, 28, was born on March 3, 1986, in the Bernal Heights neighborhood of San Francisco, California, to parents Refugio Nieto and Elvira Nieto (née Rodriguez), Mexican immigrants from the town of Tarimoro, Guanajuato.

In 2007, Nieto obtained a California state license to work as a security guard. Nieto graduated from the City College of San Francisco, with a concentration in criminal justice. During this time he held an internship at the City of San Francisco's juvenile probation department.

Nieto worked as a bouncer at a local nightclub. Around 7:00 pm on the night of March 21, 2014, he was sitting on a bench of the hilltop park called "Bernal Heights Park", eating his dinner, a burrito, before heading for work, he was wearing a red San Francisco 49ers jacket, black 49ers cap, white t-shirt, and black pants. Under his 49ers jacket, he wore a holstered taser that he used for his job as a bouncer. A local resident named Evan Snow was walking his dog near Nieto. Snow's dog Luna was unleashed, barking and chased Nieto up onto a bench trying to get at his food. Nieto and Snow conversed briefly and went their separate ways. Snow allegedly used racial slurs and texted a friend that "in another state like Florida, I would have been justified in shooting Mr. Nieto that night." Tim Isgitt and partner Justin Fritz were walking their dog shortly thereafter. Noting a rattled Nieto who had his hand on a handgun, Fritz called 911, reporting a man with a handgun wearing a red jacket.

One witness who did see Nieto shortly after Isgitt and Fritz, longtime Bernal Heights resident Robin Bullard who was walking his own dog in the park, testified that there was nothing alarming about him. "He was just sitting there," Bullard said.

Police Lieutenant Jason Sawyer and Officer Richard Schiff responded to the call and confronted Nieto as he was walking on a path in the same park. They testified that he pointed the taser at them when asked to show his hands, prompting them to open fire on Nieto. Officers Roger Morse and Nathan Chew provided backup, and later fired 14 rounds at Nieto, claiming they saw muzzle fire. According to a report by the city's District Attorney George Gascón, the officers fired a total of 59 shots: Schiff went through an entire magazine, shooting 23 bullets at Nieto while Sawyer fired 20 bullets, allegedly in response to Nieto pointing a taser, which they mistook for a pistol.

Alex's parents retained the Law Offices of John Burris and filed a federal civil rights claim arguing the police wrongfully shot their son. The trial ended on March 10, 2016, and a jury unanimously cleared the four officers of all charges. It was found that the taser's clock, which showed that the weapon's trigger had been pulled. Nieto's prior issues with mental health were discussed, as toxicology reports found he was not on medication when he was killed. Also discussed were two separate incidents in 2011 when Nieto had contact with law enforcement and resulted in 72-hour mental health holds. The family argued that the police used excessive force and that there was contradictory evidence and details about what happened.