A longtime Los Angeles County sheriff's deputy was arrested Wednesday on suspicion of murder, attempted murder and gun charges in connection with a fatal Father's Day shooting in Los Angeles.

Deputy Francisco Gamez, 41, has been booked into a jail and is being held on $4 million bail, according to the Los Angeles Police Department.

Gamez is suspected of having been involved in the June slaying of Armando Casillas, 38, outside of the victim's parents' home in the Sylmar area. Gamez was not on duty at the time of the incident.

Shortly after 11 a.m. (2 p.m. ET) on June 17, residents flagged down patrol officers and Casillas was found suffering from a gunshot wound. He was transported to a hospital and pronounced dead.

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A second victim was shot at but not injured, police said. Investigators said the shooter fired from a car.

Detectives from the Mission Homicide and Robbery Homicide divisions investigated the case, and are preparing the case for filing with the District Attorney's Office.

Gamez has been with the department for 17 years and has worked out of West Hollywood since 2005. He has been on paid leave from the Sheriff's Department since July.