This is the moment a US cop is knocked to the floor unconscious while shooting dead a suspect who manages to swing a metal pipe against his head before collapsing.

The officer-involved shooting took place in the city of Rockford in Winnebago County in the US state of Illinois on 10th April, and the local authorities released the body-cam footage on Monday evening.

The Winnebago County Sheriff’s Office said officers were called to the scene of a domestic disturbance at around 5.45pm after the wife of the suspect, identified as Faustin Guetigo, a migrant from the Central African Republic, called for help.

In one video, a cop is seen talking with Guetigo outside the home and trying to place him under arrest.

The suspect fights off the cop and moves towards the apartment. The officer tells him to remain outside as he needs to talk to him, but Guetigo goes inside the property.

At the same time, backup officers arrive on the scene and take up positions in and around the house.

Guetigo’s wife Rose Ndoroum gave officers the keys to the house, according to the police.

Two officers went inside, including Sergeant Joe Broullard who saw the suspect coming up the stairs with a metal pipe in his hand.

The cop ordered Guetigo to drop the weapon several times, however the suspect continued advancing up the stairs.

In the footage, Sergeant Broullard shoots at Guetigo multiple times before he manages to swing the pipe against his head.

Sergeant Broullard’s body-cam shows him falling to the ground next to the suspect’s body and letting out a groan.

The police said he was knocked out by the blow.

Outside the apartment, Deputy Eiten also fired his gun and shattered the glass of the door.

Sergeant Broullard and Guetigo were both taken to hospital.

The suspect died in hospital of his injuries while Sergeant Broullard was treated and later discharged.

The police said on Facebook: “In an effort to be transparent, the Winnebago County Sheriff’s Office is releasing a video news release of the deputy involved shooting.

“The Sheriff’s Office plans to release all the video recorded from this incident in the coming days. The Winnebago Boone County Integrity Task Force is conducting the investigation, so the Sheriff’s Office cannot provide additional comments at this time.”

The internal investigation into the officer-involved shooting is ongoing.