SULLIVAN COUNTY, Tenn. -

Investigators returned to the scene today, where a deadly crash shut down Interstate-81 late Saturday night.

This morning the Tennessee Highway Patrol's Critical Incident Response team closed the road to reconstruct the accident. Troopers say an 18-wheeler driven by 54-year-old Carl Osburn hit a car from behind near exit 74 in Sullivan County. Osburn and the driver of the car, 81-year-old Dennis Dawson, were killed.

Sergeant Paul Mooningham from the Tennessee Highway Patrol says, their reconstruction confirms their initial findings. "It's a very tragic event. It could have been prevented with someone paying attention. We still don't know what was going on with the truck driver, but we've got labs that will be coming back at some point to see if there were any problems there. Otherwise we have no braking coming in prior to impact," he said.

We also learned the passenger in the car, Connie Dawson, remains in the hospital in critical condition