PORT ALLEN — West Baton Rouge Parish deputies said Thursday they had arrested a Port Allen man on drug and weapons charges.

Robert Williams, 29, was picked up Monday after a traffic stop. He was accused of simple possession of marijuana, possession of a machine gun, possession of a firearm by a felon and possession of a firearm by someone convicted of domestic abuse battery.

Deputies said a firearm on Williams had been illegally modified with a "switch" that turned it into a machine gun.