TAUNTON, Mass. — Authorities are trying to determine why a man went on a stabbing rampage in Massachusetts, killing two people and assaulting and stabbing more in a house and a shopping mall before being shot dead by a fast-acting off-duty sheriff’s deputy.

The suspect in the attacks was identified as Arthur DaRosa, of Taunton.

“Tragedy has certainly hit the city of Taunton hard here this evening,” Taunton Mayor Tom Hoye said during a news conference late Tuesday about the bloodshed.

Authorities said it all began when DaRosa, 28, crashed a car outside of a house in the city, about 40 miles south of Boston. He walked inside the home and stabbed two women. An 80-year-old was taken to a hospital, where she later died. The other woman was being treated for life-threatening injuries.

DaRosa then drove to the Silver City Galleria mall, where he crashed into the front of a Macy’s department store, authorities said.

“He then exited the vehicle, assaulted multiple people inside Macy’s before making his way on foot to Bertucci’s Italian restaurant,” said Bristol County District Attorney Thomas M. Quinn III.

Once inside the restaurant, he stabbed two people, including a 56-year-old man who later died, Quinn said. An off-duty sheriff’s deputy intervened and shot DaRosa once. The suspect was taken to a hospital, where he was pronounced dead.