Search warrants show police found a shot glass and a plastic bag that smelled like marijuana in the car.
Sixteen-year-old Garrett Prince was driving the SUV that slammed into a tree in north Raleigh on Jan. 7.
Seventeen-year-old Liz Molloy was killed in the crash.
Prince was indicted Monday on felony death by motor vehicle charges.
Warrants also show investigators are searching Prince's cell phone records, trying to get more information about what happened before the crash.
Several people have been charged with buying alcohol for the teens.