A four-month undercover investigation into alleged illegal drug activity at Patrick Henry and University City high schools resulted Wednesday in the arrests of 15 students, authorities reported. Police took the teenagers into custody Wednesday morning and booked them on suspicion of narcotics offenses, including possession and possession for sale, San Diego Police Department acting Capt. Shelley Zimmerman said. The arrestees included two 18-year-olds -- Patrick Henry students Brent Binger and Terry Metsch. The others, including one girl, are minors whose names were withheld because they are juveniles. During the probe, undercover SDPD officers posed as students and bought narcotics, including marijuana, Ecstasy, psychedelic mushrooms and prescription medications, on or near the two campuses, Zimmerman said. Two of the detainees, one from each campus, were carrying stashes of cannabis when they were taken into custody, according to police. Authorities plan to seek an arrest warrant for a 16th teen, a former UCHS student who has moved to Ohio, Zimmerman said.