A Honolulu police officer testified this morning in the Toby Stangel’s shooting spree trial that he saw the flash of a gunshot and later discovered a bullet had hit his motorcycle’s gasoline tank.

Brandon Ogasawara said he was assisting in a traffic stop with other officers at the Moanalua Freeway near the Aiea off ramp when they saw a car stop.

He said as he took a half step toward the car, another officer yelled, “Gun.”

“The muzzle flash went off,” Ogasawara testified.

He said he dove to his left and ducked behind a police car.

The officer said he heard three shots, then two more as the car slowly moved and later drove off westbound on the H-1 freeway.

Ogasawara said he later noticed gas leaking from his motorcycle.

Stangel, 30, is charged with murder and attempted murder counts for allegedly going on a 17-minute shooting rampage from Waialae Avenue to the H-1 freeway early June 3, 2011.

He is accused of murdering a woman, wounding two other motorists and shooting at two police officers, including Ogasawara.

If convicted of the charges, Stangel faces a mandatory life term in prison without parole, the state’s harshest sentence.