A man and a woman found deceased in a car along the road of a Crystal Lake neighborhood earlier this month have died from accidental carbon monoxide poisoning, officials reported Wednesday.

Yeisimar Morales-Sanchez, a 20-year-old Crystal Lake resident, and Kirby Graham, 32 and of Grayslake, were found dead in a car on the morning of Nov. 4 at the 700 block of Coventry Lane by Crystal Lake police and fire rescue departments. Police received a call at 5:32 a.m. of “two people possibly asleep in a vehicle parked on the roadway,” according to a Crystal Lake Police Department news release.

Officers arrived to a woman and a man unresponsive with “no obvious signs of injury,” officials said. Life-saving measures were attempted but were ultimately unsuccessful, and the two people were pronounced dead at the scene.

Both Morales-Sanchez and Graham were determined to have died from “carbon monoxide toxicity because of a defective exhaust system of the vehicle” that was driven by Graham, McHenry County Coroner Michael Rein said in a news release. The two people were co-workers, Crystal Lake Deputy Police Chief Richard Neumann said.

Graham’s car was a 2015 Kia Optima, Neumann said.

The manner of death is found to be an accident by the coroner’s office and the Crystal Lake police and fire departments.