AURORA, Colo. (KDVR) — Investigators continue trying to determine who was at fault in a deadly crash involving an officer with the Aurora Police Department.

A man died after being hit by the Aurora Police squad car as the officer was responding to a 911 call.

The patrol car had what is called a black box. That box is expected to have crucial information in this case.

Police car black box has detailed information

The Aurora Police SUV collided with a Toyota Corolla on Saturday night. The crash caused the officer’s Chevrolet Tahoe to roll several times, leaving the officer trapped.

Now, Aurora’s interim police chief said the police cruiser’s black box will be used in the investigation, for which no witnesses have been found so far.

“The thing about traffic collisions, the physical evidence really will give you, even without a witness, a great amount of information,” interim Aurora Police Chief Art Acevedo said.

The black box can, among other things, tell how fast a patrol car was going, if the seatbelts were being worn and if brakes were applied, according to former police officer and private investigator James Allbee.

“It’s (the blackbox) pretty good at capturing everything that vehicle is doing just prior to any type of incident,” Allbee said.

Investigators say the police officer was headed north on Chambers Road in the crash with the Corolla. Investigators say the driver of the Corolla had a stop sign but did not yield to oncoming traffic.

Colorado State Patrol investigating crash

Colorado State Patrol is now conducting an outside investigation regarding the actions of both the man who was killed and the officer.

“If he’s driving within the speed limit or a reasonable amount in excess of, and the only reason this (accident) happens is because somebody blew a stop sign, that could be the officer doing everything right,” FOX31 legal analyst George Brauchler said.

The officer was responding after a 911 caller reported a break-in at a residence. State Patrol said it was a non-emergency call. The officer did not have his lights and sirens activated.

One of the big questions now is how fast was the officer driving and who was at fault.

The officer has been identified as Eduardo Landeros. Landeros was released from the hospital Sunday morning.

The identity of the man who was killed has not been released.