The man has been identified as 30-year-old David Gorski, from Libertyville. According to the coroner, the cause of death was a gunshot that traveled through his right arm and into his chest. The death is being ruled a homicide.
About 11:30 p.m. on Friday, officers were sent to the area of Milwaukee Avenue and Hollister Drive to check on a driver who was slumped inside his vehicle, according to a statement from the Lake County Major Crimes Task Force.
Officers found an adult male unresponsive inside a dark colored Volkswagen Jetta, police said. He was taken to Condell Medical Center in Libertyville, where he was pronounced dead. A preliminary investigation showed he suffered a gunshot wound.
Police said a person of interest in the case was taken into custody, but did not provide additional details.
Anyone with information was asked to contact the Libertyville Police Department at (847) 362-8310.
The Sun-Times Media Wire contributed to this report.