A man shot and killed Saturday by Gwinnett County police was unarmed, and an officer was injured by police gunfire, authorities said.

Robert Coleman was shot by police officers responding Saturday afternoon to reports of a stabbing at one home and a burglary about three blocks away near Lawrenceville, police said.

A pair of responding officers determined that the 30-year-old Coleman was a suspect in the stabbing and followed him to a second home, in the 3800 block of Smokemist Trace, where they found the front door kicked open, according to police.

Gwinnett County police spokesman Cpl. Jake Smith said Coleman “charged and physically attacked” one officer inside the home, and the officer – who feared for his life – opened fire.

“The secondary officer also fired shots at Coleman, fearing for the life of the primary officer,” Smith said.

Coleman, of Flowery Branch, was hit and died at the scene, authorities said.

The knife used in the stabbing was found at the first crime scene in the 3600 block of Willow Wood Way, and no other weapons were located there or at the scene of the shooting on Smokemist Trace, police said.

Investigators considered the officer’s gunshot wound a result of “friendly fire,” Smith said.

It is unclear, however, who fired the shot that injured the officer.

The injured officer was treated and released from a nearby hospital the night of the shooting and will require further treatment before he can return to duty, Smith said.

Both officers remain on administrative leave while the Gwinnett police Deadly Force Investigation Team investigates the incident, police said.