Police investigating an explosion outside a prosecutor's office in Southern Oregon are looking for a sports car seen speeding from the area just after the blast. It's described as a dark, two-door convertible.

Medford Police Chief Tim George said Thursday a person who lives near the Jackson County district attorney's office was outside about 4:30 a.m. Wednesday, heard the blast and then saw the car go by.

George says investigators don't know whether the car is connected to the improvised explosive device, but they want to talk to the driver.

Investigators say they are still looking for two people seen running from the area. One was reported carrying a flashlight.

The explosive partially detonated early Wednesday, blowing out windows, but doing no serious damage.