NEW YORK (NYTIMES) - The Illinois State Police said on Thursday (Oct 22) that they were investigating the killing of a 19-year-old black man by a police officer in a city north of Chicago, the latest police shooting to set off protests amid nationwide demonstrations against police violence and racial injustice.

The police in Waukegan, Illinois, said that the man, Mr Marcellis Stinnette, was shot on Tuesday night when the car he was riding in went into reverse towards a police officer who had been approaching during an investigation.

The officer, whose name was not released, fired his semi-automatic pistol into the car, killing Mr Stinnette and seriously injuring the driver, whom the police identified as a black woman in her 20s from Waukegan.

The Waukegan police said the officer, a Hispanic man who had been with department for five years, had opened fire "in fear for his safety".

The police did not describe how far the officer was from the car, how fast it was moving or any other details of the shooting, which prompted outrage among protesters and family members of Mr Stinnette and the driver. No gun was found inside the car, the police said.

On Thursday, demonstrators in Waukegan, a city of about 86,000, 68km north of Chicago, called for the Department of Justice to take over the investigation into the shooting, saying they did not trust the Illinois State Police to investigate the Waukegan police.

"The police cannot police the police, and they cannot investigate and they cannot give us fair justice," Ms Satrese Stallworth, a relative of Mr Stinnette, said, according to a livestream of the demonstration on Facebook.

"And, yes, we are seeking justice for Marcellis Stinnette."

Waukegan police officers are equipped with body cameras and cameras in their squad cars, and footage of the encounter has been turned over to the state police, according to the Waukegan police. The authorities said it could be weeks before the video is released to the public.

Ms Stallworth said the family had many unanswered questions about the shooting.

"We are seeking that someone be held accountable because this looks like murder," she said.

Ms Clifftina Johnson said her daughter had been shot while driving the car and had undergone surgery for her injuries at a hospital on Thursday. She urged the demonstrators to speak out for justice.

"You have to stand and speak for the ones who are already gone," she said.

The shooting came five months after Mr George Floyd, a 46-year-old black man, died after he was handcuffed and pinned to the ground under the knee of a white police officer in Minneapolis. It also happened just 26km south of Kenosha, Wisconsin, where Jacob Blake, a 29-year-old black man, was left partly paralysed in August after a white police officer shot him seven times in the back.

Relatives of both Mr Floyd and Blake spoke at Thursday's demonstration in Waukegan.

"All of our families are standing together - we are one family and we are united," Ms Letetra Widman, Blake's sister, said.

"We will not allow you all to just treat them like they're nothing, just because they didn't have a viral video, just because their name isn't in lights. We're going to share this spotlight."

The Waukegan police said the encounter began at 11.55pm on Tuesday, when an officer was investigating a car with two people inside. The police did not say what the officer had been investigating, but said the car fled from the officer.

Moments later, another officer spotted the car and, while he was out of his police car, approached it. At that point, "it began to reverse" towards the officer, who opened fire, the Waukegan police said.

Mr Stinnette died of injuries from a gunshot, according to the Lake County Coroner's Office, which said that toxicology results were pending. The driver was expected to survive, the police said. Both officers have been placed on administrative leave.

Mr Michael Nerheim, the Lake County state's attorney, said the Waukegan Police Department had called on the Illinois State Police to conduct a thorough, independent investigation into the shooting.

Mr Nerheim said that once that investigation, which can take several weeks to complete, is finished, the findings will be turned over to him, at which point he will determine whether the officers broke any laws.

Mr Nerheim said that once his review was complete, he would also release the entire case file, including any video of the shooting.

"Should it be determined the officers violated a law, they will be criminally charged," Mr Nerheim said in a statement.

"If laws were not broken, I will write up a detailed statement that will completely review the facts, show the evidence, explain applicable laws, and give our reasoning for the final decision."

Waukegan's mayor, Mr Sam Cunningham, said he knew the Stinnette family personally. He said he wanted police video of the shooting released as quickly as possible, and he appealed to residents to turn over any video that they might have taken of the encounter.

"Yes, I'm nervous," he told reporters.

"I'm nervous because there's a lot of uncertainty out there. There's a lot of rumours flying around. That's why we're begging - whatever information that you have, get it to us. Whatever footage that you may have, get it to us."