A 19-year-old restaurant dishwasher was busted for allegedly trafficking heroin Wednesday after he sold the narcotic four times to undercover police officers over the past three weeks, police said.Ruben O. Ramos, of 158 Chestnut St., Lynn, was arrested and charged with trafficking over 14 grams of a class A drug (heroin), three counts of distribution of heroin, distribution of a class B drug (cocaine), possession of a class D drug (marijuana) and three count of a drug violation in a school zone shortly after 4:30 p.m. Wednesday ? just minutes after he allegedly sold heroin to an undercover officer at the corner of Mall Street and Western Avenue.Using the street name “Le Fe,” Ramos allegedly sold to undercover officers in the Lynn Drug Task Force, which consists of local and state police, after police were provided with Ramos’ cell phone number during an investigation into a drug ring.Ramos allegedly sold drugs to the officer inside a Union Street pizza shop on Jan. 24, outside a West Green Street home on Jan. 28, in front of a Mall Street home on Feb. 8 and at the corner of Mall Street and Western Avenue on Tuesday. On Feb. 8, he included cocaine with the sale of heroin, police said.Lynn District Court Judge Stacey Fortes-White ordered Ramos held on $25,000 cash bail during his arraignment Thursday after prosecutors had asked for $75,000 cash bail. Ramos is due back in court March 13 for a probable cause hearing.