(CNN) -- A sheriff's deputy pleaded not guilty Wednesday to charges stemming from the shooting of an unarmed Iraq war veteran in San Bernardino, California -- an incident captured in grainy, amateur video earlier this year.

San Bernardino County Sheriff's Deputy Ivory Webb surrendered to authorities before the hearing. He is charged with attempted voluntary manslaughter and a weapons charge in the January 29 incident, which began when police briefly gave chase to a car in which Air Force security officer Elio Carrion was a passenger.

The charges against Webb carry a special condition of great bodily injury, and if he's convicted, he could be sentenced to 18 years in prison.

Webb wore a dark suit and spoke only once during Wednesday's arraignment, saying, "Yes, your honor," after the judge asked a question about waiving his right to a speedy preliminary hearing.

San Bernardino County Superior Court Judge Michael A. Smith rejected a defense motion to reduce Webb's $100,000 bail to $50,000, noting he had previously reduced the bail from $175,000. However, because Webb surrendered voluntarily, the judge gave him until 4 p.m. Friday to be booked and post bail.

Webb is scheduled to appear again in court April 28 for a status conference on the case.

Carrion was shot after the driver of a blue Corvette carrying the war veteran briefly tried to elude police in a chase that exceeded 100 mph at times. The chase ended when the driver crashed into a brick wall.

In the dark and grainy video taken by witness Jose Luis Valdez, Carrion is lying on the ground with Webb standing over him, gun drawn.

"Get up!" the deputy shouts.

"OK," says Carrion.

"Get up!" the deputy repeats.

"I'm going to get up," Carrion says, and as he begins to rise, the deputy fires three shots, later said to have hit Carrion in the chest, leg and shoulder.

Moaning and on the ground, Carrion explains that he's a war veteran. "I mean you no harm," he tells the deputy.

"Shut the [expletive] up!" the deputy shouts twice.

The deputy then says he has "one down" and tells Carrion again, "Shut the [expletive] up."

"You don't get up!"

A witness can be heard in the background, telling the deputy, "You told him to get up."

Sheriff Gary Penrod said an internal sheriff's department investigation is ongoing. Webb, a nine-year veteran of the department, has been placed on administrative leave until the investigation is complete.

The FBI also is looking into possible civil rights violations.

Carrion, who spent six months in Iraq and had only recently returned to the United States when the shooting occurred, spent several days in the hospital and is now recovering from his injuries at home, according to a statement from the district attorney's office, which pressed charges against Webb on Tuesday.

Prosecutors also announced Tuesday they are charging the alleged driver in the car chase, Luis Escobedo, with felony attempting to evade police while driving recklessly and misdemeanor driving under the influence.