April 6 (UPI) -- Sean Penn's son was arrested for drugs in Nebraska on Wednesday, police said.
The trooper said he found in the car 14 grams of marijuana, four amphetamine pills and three grams of mushrooms.
Hopper was arrested for the mushrooms, which got him a possession of a controlled substance charge, and another charge for having less than an ounce of marijuana.
Wittkamp, 26, was arrested for two counts of possession of controlled substances for the mushrooms and amphetamines, Page Six reported.
Hopper, an actor whose latest role was in the Netflix film, War Machine, has spoken out in the past about his problems with drug addiction, including methamphetamines.
"I was doing a lot of stuff," Hopper told ES Magazine last year. "But meth was the main one that brought me down. I went to rehab because I woke up in a hospital and my dad was like, 'Rehab? Or bus bench?' I was like, 'I'll take the bed.'"