LA HONDA — A 40-year-old La Honda man was arrested on felony charges including child endangerment after San Mateo County sheriff’s deputies allegedly found “illegal assault rifles” and a pipe bomb in a room where his 1-year-old son was present.

Deputies went to a home on the 900 block of Portola State Park Road on May 23 to conduct a parole search and serve an arrest warrant for 33-year-old Sean Collins, the sheriff’s office said in a news release Tuesday. Items believed to be used in the manufacture of firearms were allegedly found in a common room belonging to his roommate, Karl Waltenbaugh.

A second search warrant was authorized and deputies discovered a “large amount of illegal assault rifles, high-capacity magazines, body armor, an active pipe bomb and equipment for manufacturing firearms” in Waltenbaugh’s room, according to the sheriff’s office.

Waltenbaugh’s son was allegedly present in the room where the illicit items were found.

The sheriff’s office said its bomb squad disposed of the pipe bomb and an agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives helped collect evidence.

Waltenbaugh was arrested and booked into jail on felony charges of possession of an assault rifle, possession of a destructive device and child endangerment. Collins was also arrested and booked into jail on a misdemeanor charge of possession of ammunition by a prohibited person, as well as a parole violation and a $15,000 warrant.

Anyone with information related to the case can contact the sheriff’s office anonymous tip line at 800-547-2700.