The New Haven Police Department’s Tactical Narcotics Unit on Tuesday afternoon arrested Donald Griffin, 33, for the alleged sale of narcotics at 1329 Chapel St., three blocks from Pierson College. As the detectives were leaving that residence, they saw a street-level sale going on in front of 1345 Chapel St. and subsequently arrested Osario Zuiry, 32, for illegal possession of 48 Oxycontin pills and, in addition, intent to sell within 1,500 feet of a school. Since the narcotics unit was reinstated in February, it has made 80 arrests and seized 639.06 grams of crack, 825.4 grams of marijuana, 26.4 grams of heroin, 19 ecstasy pills, 50 Oxycontin pills and $42,766 in cash.