The 45-year-old mayor was shot at a townhome in a gated complex in the 6300 block of East Gage Avenue shortly after 2:30 p.m.
Los Angeles County Sheriff's Department Lt. Steve Jauch says the mayor got into an argument with his wife, and their 19-year-old son tried to intervene. Daniel Crespo and his son, Daniel Crespo, Jr., began fighting. That's when Lyvette Crespo got a gun and shot her husband several times in the torso.
He was transported to a local hospital, where he was shortly pronounced dead.
Authorities questioned both Lyvette Crespo and her son, who went to the station voluntarily. No arrests were made, but both were voluntarily staying at the Bell Gardens Police Department.
The sheriff's department is expected to present its case to the district attorney, who will determine if charges will be filed.
Crespo had been a county deputy probation officer for the past 15 years. He was elected to the City Council in 2001.
The city website says Crespo married his high school sweetheart, Lyvette Crespo, in 1986. He had been married ever since.
The investigation is ongoing. Anyone with further information was asked to contact the Los Angeles County Sheriff's Department's Homicide Bureau at (323) 890-5500.