RICHMOND, Calif. -- Homicide investigators searched Monday for the grey Ford Explorer of a gunman who riddled a Richmond woman’s car with a barrage of bullets on a local freeway, fatally wounding her.

Richmond Police Lt. Mark Gagin told KTVU that the shooting wasn’t a random act and was witnessed by a car driving behind the Explorer when the fatal shots were fired.

“There’s not a threat to everyone,” Gagin said. “It wasn’t like there was a sniper on the freeway bank shooting at cars randomly. The way this shooting went down we are confident that this car was targeted by the shooters. They followed it. They only shot at this vehicle and after they finished they left. They did not intimidate or threaten the witness car.”

Gagin also revealed that there were 3-4 black males in the shooter’s SUV. He added that the shooter’s vehicle raced up from behind and opened fired on the Chevrolet Monte Carlo carrying Rickeasha Washington. She was struck once and her companion was uninjured.

“What we have also been told is that there was a third vehicle – a witness vehicle – right behind the suspect when the shooting went down,” he said. “So we are confident there are witnesses to this homicide.”

Gagan said Washington was a 25-year-old mother.

The incident began at about 4:30 a.m. Sunday. Richmond officers were sent to a Valero gas station at 2401 Appian Way in Pinole after receiving the report of the shooting.

When they arrived, they found Washington mortally wounded. She was taken to a nearby hospital, where she was pronounced dead, authorities said.

A vehicle had pulled into the gas station shortly before police arrived requesting assistance. The driver said that someone in a dark sport utility vehicle fired multiple shots at his car on Interstate Highway 80 near Cutting Boulevard, according to Richmond police.

The motive for the shooting remained under investigation.

Anyone with information is asked to call Richmond homicide Detective Stina Johanson at (510) 620-6902. Callers wishing to remain anonymous are encouraged to call (510) 232-TIPS.