(CNN) -- Law enforcement officials in Seattle, Washington, vowed Sunday to catch whoever is responsible for fatally shooting a police officer and wounding a student officer as they sat in a parked patrol car.

Field training officer Timothy Brenton, 39, was reviewing details of a traffic stop with student officer Brit Sweeney when a vehicle rolled up next to the squad car shortly after 10 p.m., authorities said

People inside the vehicle fired several shots into the squad car, killing Brenton and injuring Sweeney, according to police.

The shooting was the first intentional homicide of a city police officer since 1994, Seattle Mayor Greg Nickels said.

"We will not rest until the assailant is brought to justice," Nickels said at a news conference Sunday.