There is an investigation into what caused a collision between an Erie Police cruiser and a car Friday.

It happened just after 7 a.m. at the intersection of West 11th and Sassafras St. in Erie. 

Erie Police Chief Dan Spizarny said the driver of the car was going west on West 11th. They had a green light.

The officer, who was going south on Sassafras with police lights on, had a red light.

The two collided at the intersection.

It is undetermined whether the sirens on the Erie police cruiser were on when the collision happened. 

The officer received a head injury and has been released from the hospital.

The driver of the car, a 40-year-old man, was taken to UPMC Hamot’s Trauma Center. He is in critical condition as of Friday afternoon.

Their names are not being released. 

A homeless man was hit by the car. He was taken to the hospital for observation.

His condition is not known.