WASHINGTON, July 15 (Xinhua) -- Two people, including one police, were killed Sunday in the U.S. state of Massachusetts after a man attacked them with a rock and gun.

The incident took place in Weymouth on Sunday morning, when the deceased officer Michael Chesna pulled over a man driving erratically, according to local officials.

The driver, identified as Emanuel Lopes, fled the scene, prompting Chesna to pursue.

Lopes then threw a large rock at Chesna, beating him to the ground, he then drew Chesna's gun and fired multiple shots to his head and chest. A bystander was also killed in the incident.

Other policemen who arrived at the scene managed to disarm Lopes and take him into custody. Lopes is expected to face two charges of homicide.

Two more policemen are also shot in the central state of Missouri Sunday, with the gunman still at large. The conditions of the wounded are unclear.