SAN DIEGO -- An off-duty Coronado police officer who shot San Diego Chargers linebacker Steve Foley near the football player's home testified Tuesday that he opened fire when he thought Foley reached into his waistband for a gun.

Officer Aaron Mansker's testimony came during a preliminary hearing for Lisa Maree Gaut, Foley's passenger the night Mansker followed him from downtown San Diego to Poway in the early-morning hours of Sept. 3, thinking he was a drunken driver.

Mansker said the car he was following was weaving in and out of lanes, almost hit another car, almost hit a center divider and was driving erratically at speeds between 30 and 90 mph.

Gaut, 26, is charged with felony assault with a deadly weapon with force likely to produce great bodily injury and assault with a deadly weapon on a peace officer for allegedly using Foley's restored 1971 Oldsmobile Cutlass to try to run down Mansker on the Travertine Court cul-de-sac where Foley lives and where the shooting occurred.

She also faces misdemeanor charges of driving under the influence of alcohol and driving with a blood-alcohol level above the legal limit of .08.

Mansker said Foley, 31, stopped his car around 3:30 a.m. near Travertine Court and got out of his car.

The off-duty officer -- who had gotten off work at 3 a.m. and was driving his own vehicle, not a patrol car -- said he decided the potential stop wasn't worth it, backed up and drove around Foley's vehicle up the street, not knowing it was a cul-de-sac.

Mansker said once he turned around, Foley was out of his car and walking toward him, and Gaut was driving the car slowly behind him.

The officer said he got out of his car and fired a warning shot into a berm, but Foley kept walking and Gaut kept moving the car forward.

Mansker said the vehicle suddenly went around Foley and sped toward him.

Fearing he would be crushed between the oncoming car and his car door, Mansker said he fired two shots at the hood of Foley's car.

Mansker said he backed up and saw Foley near the front of his unmarked car, lifting up his shirt.

"It wasn't the actions of a reasonable and prudent person," Mansker testified. "I thought he was going to draw a firearm and finish me."

Mansker said he fired at Foley, who went down to the ground.

"He said, `You just shot me in the knee,"' Mansker testified.

The officer said Foley started to get up and reach in his waistband again, and he fired a few more rounds, sending the Charger linebacker to the ground again.

Foley -- who was shot three times -- has been placed on the Chargers' "reserve non-football injury" list, a move that has sidelined him for the season, costing him his $1.65 million salary.

He was charged last week with two counts of misdemeanor DUI.

Mansker said he initially followed Foley -- whom he did not know was the driver -- to the Pomerado Road offramp from northbound Interstate 15.

Mansker said he pulled up next to Foley near Pomerado and Spring Canyon roads, identified himself as a police officer, and ordered him to pull over.

Mansker said the driver uttered an expletive, looked around the vehicle like something shouldn't be there, then drove off.

A few minutes later, Foley stopped in the road again, got out of his car and approached Mansker, the officer testified.

"Where was your focus?" prosecutor James Koerber asked Mansker.

"My focus is on his hands," the officer testified.

Mansker said he pulled out his off-duty service weapon when Foley initially refused his orders to stop. He said Foley ended up stopping at his car door.

The officer said Foley looked at him and said, "That's a BB gun," and walked back to his car and drove off.

According to court testimony, Mansker tried to get units from the San Diego Police Department and the San Diego County Sheriff's Department to execute a traffic stop on Foley's car.

By the time sheriff's deputies arrived at the cul-de-sac, the shooting had already happened, according to court testimony.

During the course of the subsequent investigation, it was learned that Foley thought he was either being followed by a fan or a would-be carjacker, sheriff's homicide Detective Thomas Ness wrote in an affidavit for a search warrant.

According to search warrant affidavits, a sample of Foley's blood revealed a .23 blood-alcohol level, taken at 4:29 a.m. Sept. 3.

On Sept. 13, Ness said he learned from the Sheriff's Crime Lab that Foley's blood-alcohol level measured .16 and Gaut's blood-alcohol level measured .15.

According to the affidavits, Ness said it was explained to him that hospital blood-alcohol test results consistently measure higher than a criminalist's results due to hospital testing methods.

Mansker, 23, will remain on administrative leave pending resolution of investigations into the shooting, according to the Coronado Police Department.

He will continue his testimony Wednesday.