EAST LIBERTY, Pa. — A 26-year-old woman was arrested Wednesday after police said undercover agents purchased heroin from the woman while she was working at the East Liberty McDonald’s. According to Mike Manko, a spokesperson for Allegheny County District Attorney Stephen Zappala, authorities received information that heroin was being sold by an employee at the McDonald’s Restaurant on Penn Avenue in the Bakery Square section of East Liberty. Manko said several law enforcement officers set up a controlled buy at the restaurant Wednesday. Investigators said the customer looking for heroin was instructed to go through the drive-through lane and say,...