A man is in custody in Massachusetts after striking and killing a Waltham police officer and a National Grid utility worker with a car and then stealing another officer's car on Wednesday, officials say.

Two other National Grid utility workers were injured in the crash.

The suspect, identified as Peter Simon, 54, of Woodsville, New Hampshire, has been charged with two counts of manslaughter and armed robbery.

According to the Middlesex County District Attorney's Office, Simon was driving a pickup truck eastbound on Totten Pond Road in Waltham when he pulled to the side of the road and suddenly turned back into the roadway in an attempt to execute a U-turn.

Simon then continued driving for approximately a quarter mile before fatally striking Waltham police officer Paul Tracey, 58, of Waltham and the utility worker, identified as a 36-year-old man from Cambridge.

Tracey was working police detail on a National Grid work site at the time of the crash, the Middlesex County DA's office said in a news release.

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Authorities say suspect stole other Waltham police officer's car, led officers on chase

Authorities say after striking the victims, Simon continued on, striking multiple other vehicles before abandoning his truck and fleeing on foot. While running, Simon encountered another Waltham police officer who had responded to the scene, and allegedly pulled a knife on the officer before stealing his police car and fleeing.

Simon crashed the cruiser and fled on foot once again, but was apprehended by Waltham police after a brief foot chase, the Middlesex County DA's office said.

This is an active and ongoing investigation being conducted by the Middlesex District Attorney’s Office, Waltham Police and Massachusetts State Police Detectives assigned to the District Attorney’s Office, according to the Middlesex DA's office.