Santa Paula Police arrested a man they say had planned to attack their headquarters.
Investigators say the man had a gun, ammunition, protective gear, and information on how to make an illegal automatic weapon at his home.
Police got a tip that a man said he would attack the police station and kill officers when he returned home from a trip to Idaho. He also threatened his relatives if they notified authorities.
The 70-year-old suspect was arrested when he returned to Ventura County on Wednesday.
Authorities say the man was upset over an ongoing Ventura County court case from last year. Ventura Police had seized 130 weapons from his home, including automatic weapons and unregistered ghost guns.