SAN FRANCISCO (KRON)—A San Francisco police officer has been arrested for having an assault rifle and for making one on Tuesday.

Thomas Abrahamsen, 50, surrendered to authorities and was booked into the San Francisco County Jail.

Abrahamsen has been charged with one felony count of possessing a firearm and one felony count of manufacturing an assault weapon.

The internal affairs division of the department conducted an internal investigation that lead to the arrest.

Abrahamsen has been on the force for 18 years and is on unpaid administrative leave.

The SFPD Internal Affairs has given all their information about their investigation to the District Attorney’s Office.