The Lake County Coroner's Office on Monday said 11-year-old Alonso Tiscareno and 16-year-old Antony Tiscareno, both of Wadsworth, died from blunt force injuries on the scene, as a result of the crash.
Police previously said they were from Zion.
Two 20-year-old men, one from Zion and another from Beach Park, were hospitalized in critical condition.
Officials did not provide an update on their conditions Monday.
Authorities said the crash took place just after 11:35 p.m. Friday in the 1700-block of Grand Avenue in Lindenhurst.
The Lake Villa Fire Protection District and Lindenhurst Police Department responded to a single-vehicle crash with injuries.
Investigators said a vehicle traveling east on Grand Avenue left the roadway, and hit a tree.
It was not immediately clear why the vehicle left the road.
When first responders arrived, the vehicle was on fire, with the two children and two men inside.
Lindenhurst police and the Lake County Major Crash Assistance Team are investigating the deadly crash.
Anyone with information is asked to call Lindenhurst police at 847-356-5400.
The video in the player above is from an earlier report.