A student who lived in a residence at UC Davis has been charged with three drug offenses after he surrendered himself to authorities at the Yolo County jail Tuesday. Matthew Eaker, 18, of Rocklin has been charged with possession for sales of marijuana, possession for sales of psilocybin (hallucinogenic mushrooms) and possession of concentrated cannabis. He was released on $15,000 bail. Campus police searched the room occupied by Eaker and his roommate, Peter Reis of Menlo Park, after a March 13 incident in their Webster Hall residence. Following the search, Reis was charged with possession for sales of marijuana, hashish and psilocybin (hallucinogenic mushrooms), and a warrant was issued for Eaker's arrest. Detective Sgt. Joyce Souza of the UC Davis Police Department says campus police responded to a 911 call after two juveniles reportedly entered the residence to visit Reis. During the visit, a 17-year-old juvenile allegedly pulled a hammer out of his backpack and assaulted his companion and Reis. The juvenile was later sent to Yolo County Juvenile Hall on two counts of assault with a deadly weapon.