Two men and a woman are accused of stealing $4,500 worth of items, including $3,000 in winter coats, from a Medford T.J. Maxx.
Detectives say one of the suspects displayed a knife when confronted by an employee.
Police say the three took off in a black Nissan or Infiniti sedan with aftermarket rims.
A cash reward is being offered for any information that leads to an arrest.