A teenager killed by a police officer in Illinois had just been involved in a scuffle while trying to steal a handgun during a street sale, police said.

Zion police have said Justus Howell, 17, of Waukegan, was shot Saturday afternoon by an officer responding to a call about an altercation.

On Monday, the Lake County Coroner's Office issued a statement saying an autopsy showed one bullet struck Howell in the left side of his back, penetrating his heart, spleen and liver, and the second bullet struck him on the right side of his back. Tests to determine whether drugs were in the victim's system are pending.

In a statement Monday evening, Zion Police Chief Steve Dumyahn declined to comment on the autopsy, saying police had not seen the report.

But he provided additional details about the moments leading up to the shooting, saying Howell had just been involved in a gun deal with 18-year-old Tramond Peet, who appeared in court Monday on weapons charges.

Peet told investigators that he met up with Howell to sell him a handgun but that Howell tried to take it without paying, Dumyahn said. Peet said the gun discharged into the ground during a struggle and that Howell pointed the gun at him. Peet said he released the handgun when he heard police cars approaching.

He told police investigators that he saw officers running after Howell, heard them giving Howell commands and then heard gunshots.

Peet was later arrested and appeared in bond court Monday on two counts of aggravated unlawful use of a weapon. He was being held on a $15,000 bond.

Dumyahn said the officer who shot Howell is a nine-year veteran who has been placed on administrative leave. He did not release the officer's name or other information, including his race.

Howell was black, and Lake County NAACP president Jennifer Witherspoon said his relatives have asked her organization to speak on their behalf.

Witherspoon said authorities told the NAACP that they have videotape of the scuffle between Peet and Howell but can't yet say what led the officer to shoot Howell.

"Whether it was a mistake on his part or a mistake on the police's part, they want answers to make sure something like this never happens again," she said.

The teen's death comes months after an unarmed black 18-year-old was shot and killed by a white police officer in Ferguson, Missouri — an incident that sparked protests and heightened concerns about how minorities are treated by police around country.

"Here in America, we are seeing this with too many brown and black boys," Witherspoon said.

Zion is a community of about 24,000 people along Lake Michigan about 45 miles north of Chicago, near Illinois' border with Wisconsin.

Howell was a high school junior at Waukegan Public School District 60, spokesman Nick Alajakis told the Chicago Tribune.