WOBURN - A local post office worker was arrested last Friday for distributing prescription painkillers to his co-workers after federal and regional authorities wrapped up a 10-month investigation into the illicit activity.

Detectives from the Southern Middlesex Regional Drug Task Force (SMRDTF), joined by special agents from the U.S. Post Office, arrested Patrick Rafferty, 44, of Green Street, last Friday at 5:30 p.m. as he returned to his home from work.

The 44-year-old faces two counts of distribution of a Class B substance (oxycodone) and charges for violation of a drug-free school zone.

According to police reports, U.S. Postal Service Special Agent Robert Sproull, along with SMRDTF investigators Lt. Det. Robert Rufo and Det. Angelo Piazza, interviewed two employees last Friday at Woburn's Washington Street branch about Rafferty's alleged distribution ring.

The first mail carrier reportedly admitted to recently purchasing painkillers from the 44-year-old suspect, and turned over 10 Oxycodone tablets to the investigators.

The postal service worker claimed that he purchased the prescription drugs for $100 from Rafferty and obtained them after driving the 44-year-old home to his Green Street residence.

Later in the day, a second mail carrier was interviewed who also allegedly admitted to abusing prescription painkillers for the past three to four months. According to the man, he had obtained the drugs from Rafferty on at least 20 occasions, and had met the suspect on his delivery route to arrange purchases.

Police later seized a number of Oxycodone tablets, which had reportedly been obtained through Rafferty just a day earlier, from the second employee's residence.

Rufo later confronted the 44-year-old suspect outside his residence when he was driven home by his fiancÈ, who currently does not face any charges for participating in the distribution ring.

Authorities later seized a bottle of painkillers that had been filled just a day earlier.

Counts showed that only 221 of the 360 pills included in the prescription remained, meaning that over 124 painkillers were missing — even with the recent sale of at least 15 pills to the two postal service employees being considered.

According to police reports, SMRDTF investigators first began investigating Rafferty last spring, when a confidential informant first alleged that the Green Street man was distributing painkillers from his home and personal vehicle.

In late April, an anonymous caller also accused Rafferty of selling prescription drugs.

U.S. Postal Service investigators received an anonymous complaint about the Green Street resident in early June, when a caller alleged that Rafferty was selling as many as 200 pills a month to letter carriers and U.S. Post Office employees at the Washington Street branch.