Protesters confront police in front of the Kenosha County Courthouse during a third night of protests on Tuesday night (US time) over the shooting of Jacob Blake, an African American, by a police officer. Wisconsin expanded its National Guard presence. The governor declared a state of emergency. Photo: AFP

Investigators of a shooting by a white police officer that left a black man, Jacob Blake Jr., paralyzed and the town of Kenosha, Wisconsin, torn by civil strife found a knife belonging to Blake at the scene of the confrontation, the state attorney general said on Wednesday. 

The incident sparked three nights of civil unrest that has included a wave of arson, widespread vandalism and a separate shooting that claimed two lives in Kenosha, a city of about 100,000 residents on Lake Michigan, 40 miles (60 kilometers) south of Milwaukee.

In the first official details of Sunday's shooting released by the Wisconsin Justice Department, which is probing the incident, Attorney General Josh Kaul said the knife was recovered from the driver-side front floorboard of the car Blake was leaning into when he was shot in the back.

Kaul also told a news conference that Blake, during the course of the investigation, had "admitted that he had a knife in his possession."

Blake's lawyer responded in a statement that his client posed no threat to police and disputed that he was in possession of a knife.

Kaul did not describe the knife or say whether it had anything to do with why the officer, a seven-year veteran of the Kenosha police department identified as Rusten Sheskey, had opened fire on Blake.

Kaul's briefing came shortly before the US Justice Department announced it had opened a federal civil rights inquiry into the shooting, to be conducted by the FBI in cooperation with Wisconsin authorities.

In a separate development hours earlier, a teenager was arrested and charged with shooting three people, two of whom died, during Tuesday night's protests in Kenosha.

Video footage from that incident showed a white gunman, armed with an assault-style rifle, firing at protesters who tried to subdue him, and then calmly walking away from the scene, hands in the air - his rifle hanging in front of him - as several police vehicles drive by without stopping him.

Wisconsin Lieutenant Governor Mandela Barnes said on MSNBC the suspect, later identified as Kyle Rittenhouse, 17, of Antioch, Illinois, was apparently a militia group member.

Bracing for a fourth night of possible upheavals on Wednesday, Governor Tony Evers said he was doubling the National Guard force he had ordered deployed to 500 troops, and a dusk-to-dawn curfew was imposed an hour earlier.

Reuters