An assistant Suffolk County prosecutor made the announcement during a brief court proceeding Tuesday involving 33-year-old David Laffer of Medford. He is currently being held without bail on first-degree murder charges and did not appear in court.
The specific charges returned by a grand jury were expected to be announced in the coming days.
The bloodshed occurred on Father's Day at Haven Drugs in Medford. Police say two employees and two customers were shot at point-blank range.
Laffer's wife, Melinda Brady, was arrested on charges of robbery and obstruction. She is also facing a possible upgrade in charges.
Her Tuesday court appearance was postponed to July 15.