RIVERSIDE, Calif. — Prosecutors planned a news conference Wednesday to announce charges in the shooting deaths of two Palm Springs police officers.

John Felix, 26, is expected to be charged by the Riverside County district attorney with the murder of officers Jose “Gil” Gilbert Vega and Lesley Zerebny. Other felony charges also are likely.

Felix used an assault rifle to kill the two officers who were responding to a domestic disturbance call at the California home of the suspect’s family, authorities said Tuesday.

Felix was prohibited from legally possessing firearms because of a prior felony conviction, the Sheriff’s Department said in a statement.

Felix served 18 months of a four-year sentence for assault with a gun in connection with a 2009 gang shooting. He was paroled in 2011, according to state records.

Police officers arriving at the Palm Springs home on Saturday were told by a relative that Felix had an unknown weapon.

Officers spoke with Felix through a metal screen door before he opened fire without warning, the statement said.

The officers were wearing ballistic vests as required when they are in uniform and on duty.

Another officer was treated for a gunshot wound and later released from a hospital.

Authorities declined to release a 911 recording alerting police about a problem or say who made the call.

Vega, 63, was a 35-year veteran of the force who was preparing to retire soon. Zerenby, 27, had been with the department about 18 months and her husband is a sheriff’s deputy. The couple has a 4-month old daughter.

Palm Springs had not lost an officer in the line of duty since 1962.

A public memorial will be held for the officers on Oct. 18 in the desert resort town of 45,000 people about 100 miles east of Los Angeles.