Edgar Rivera, 21

Edgar Rivera, a 21-year old Latino, was shot to death at his family's home in the 19828 Welby Way in Winnetka about 9 p.m. Wednesday, Feb. 6.

According to police, Rivera was one of three family members shot and killed by his brother, Edwin Rivera, a 20 year-old Latino.

Edwin was shot and killed by a sniper in a police standoff at shortly after 5 a.m. the following morning. During the standoff, he had allegedly shot two veteran SWAT officers, killing Officer Randal Simmons, 51, and critically injuring Officer James Veenstra, 51, who is recovering from surgery at Northridge Medical Center.

At a news conference, Deputy Chief Gary Brennan said Edwin was experiencing mental health problems, which became "progressively worse" after the death of his mother when he was 10 or 11 years old. His mother had died of cancer, KCAL 9 reported.

Police said Edwin was not a gang member, although he had a juvenile criminal record that included three convictions. The most serious came in 2004, when he was found guilty of assault with a firearm and sentenced to probation for pointing an unloaded gun at other men during an argument, police said. Between 2005 and 2006, police responded to minor disturbances at the house. In one incident two years ago, there was a drive-by shooting near the residence, but police said Edwin was not involved.

According to relatives, Rivera and his wife had emigrated from El Salvador about 25 years ago. The couple had four children, all U.S. citizens.

-- Richard Winton and Joel Rubin