VALLEJO (CBS SF) — An armed man who was killed in an officer-involved shooting in a Vallejo Taco Bell drive-thru was carrying a semi-automatic handgun stolen in Oregon, authorities said Monday.

In a news release, the Vallejo police said “the firearm was a fully loaded 40-caliber semi-automatic handgun with an extended magazine inserted in the weapon. The firearm appeared to be fully functional and has been sent to an independent crime lab for further testing.”

20-Yr-Old Rapper Killed In Vallejo Officer-Involved Shooting At Taco Bell

The gun played a pivotal role in the incident that began around 10:36 p.m. Saturday in the drive-thru lane of the Taco Bell restaurant located at 974 Admiral Callaghan Lane.

Vallejo police said an employee called 911 to report a man slumped over the driver’s seat of a Silver Mercedes was parked in the drive thru.

Officers responded to the call in order to check on the welfare of the driver. As the officers approached the Mercedes, they could see that the adult male driver was unresponsive, and that he had a handgun on his lap.

The officers found that the vehicle was locked and that the Mercedes’ transmission was in drive.

Police said the officers made efforts to stop any forward progress by the Mercedes as they assessed the situation and asked for additional resources. But the driver of the vehicle suddenly began to move.

The officers told the driver to keep his hands visible, but he allegedly reached for the handgun on his lap. In fear for their own safety, the officers opened fire.

The wounded driver was given medical assistance, but was pronounced dead at the scene. Family members identified him as 20-year-old Williebo McCoy of Vallejo, who was a rapper going by the name Williebo. A music video of his can be seen below (WARNING: Explicit language):

His family couldn’t believe that he was gone.

“He was one that had made it out of here. He really made it out,” said David Harrison, McCoy’s cousin.

A vigil was held for McCoy on Sunday evening at the waterfront at 938 Mare Island in Vallejo.

McCoy’s older brother Mark believes his that police acted too quickly and surprised the young man.

“My little brother was just shot for no reason,” he said.

“If I wake you up… if I knock on your front door and, ‘Bang bang bang!’ you’re going to jump off the bed like, ‘Who the hell is this?’ You know? Why wouldn’t you be safe while you wake him up and then [mocks bullhorn] ‘Driver, exit the car!’ Now, if he exits the car shooting, then I understand. I have to chalk that up.”

The incident was being investigated in accordance with the Solano County Fatal Incident Protocol.

The Vallejo Police Department is encouraging anyone who may be a witness or who has additional information to contact Detective Scott Yates at (707) 648-4533 or Detective Craig Long at (707) 648-4514.