'Nightmare': 4, including 2 police officers, killed in Iowa crash

Four people were killed early Saturday, including two rookie officers, when a car driving the wrong way struck their police cruiser in Des Moines, Iowa, authorities said.

The crash happened on Interstate 80 around 12:40 a.m. local time while the officers were transporting a prisoner, officials said. The crash killed the two officers, the prisoner, and the driver of the other vehicle.

At an emotional news conference Saturday morning, Des Moines police said the officers -- Susan Farrell, 30, and Carlos Puente-Morales, 34 -- had just graduated from police academy in October 2015 and were dedicated employees.

See images of the officers:

"When you're new, you go wherever you're told, and both of them did that with a smile on their faces," said Sgt. Paul Parizek, with tears in his eyes.

The officers and the other driver were wearing seat belts, although it wasn't clear if the prisoner was, officials said. Their names were not immediately released.

The last death of a Des Moines police officer in the line of duty was in December 2007, they added.

"We face a nightmare that no one ever wants to experience," Des Moines Police Chief Dana Wingert said Saturday. "Words cannot express what this loss means."

Des Moines Mayor Frank Cownie told the Des Moines Register the officers were doing a "routine" pickup of the prisoner when the crash happened.

"These are people who had dedicated their lives to public service and had bright careers that came to a tragic end," he said.