Dallas police are searching for a person who fired shots at a patrol car, injuring one of two officers inside the vehicle early Thursday morning.

In a news conference later in the day, Executive Assistant Chief of Police David Pughes said he hoped someone saw something that will help lead authorities to a suspect in the shooting that took place just after 2 a.m. on eastbound Interstate 30 before the Interstate 45 overpass.

"As the officers were traveling, they heard a couple of loud bumps, one of which was a bullet that struck the side passenger door," Pughes said. "The other one then penetrated the window on the passenger side of the vehicle."

The second shot broke the window, sending glass flying toward the officer in the passenger seat. The officers immediately drove to a nearby hospital, where it was determined the officer struck by glass suffered minor injuries.

Investigators at the scene found four shell casings, which showed the shooter fired four shots, two of which hit the car, Pughes said.

Authorities said the shooter likely fired the shots from the service road while either on foot or from inside another vehicle.

The incident happened the morning after another shooting at a Richardson apartment complex left an officer and a second person dead. The deadly shooting wasn't connected to the interstate incident and a suspect was taken into custody in that case.