A Montgomery County police officer was sentenced yesterday to 20 years in prison for shooting a man three times in the head last February after an argument over the officer's 18-year-old girlfriend.

Darryl S. Austin, 29, who was on duty and training a rookie when the shooting occurred, tearfully apologized for the incident yesterday, saying, "I'm very sorry for what happened . . . . This was an unusual case."

However, Circuit Court Judge William C. Miller cited Austin's lack of remorse and his efforts to cover up the incident in sentencing the Silver Spring resident to the maximum 30-year sentence on his attempted second-degree murder conviction.

Miller later suspended half of the sentence, but ordered an additional five-year prison term for Austin's conviction for the use of a handgun in a violent crime. Austin will be eligible for parole in about 7 1/2 years.

Austin, who is in his fourth year as a county police officer, was suspended without pay shortly after the Feb. 27 shooting. However, because the charge of attempted second-degree murder is a misdemeanor offense, Austin is considering filing a grievance for about $25,000 in back pay, according to Gary Crawford, one of his attorneys.

A police trial board hearing is scheduled Feb. 25 to consider dismissing Austin from the force, Crawford added.

Barry Helfand, a defense attorney, described the shooting yesterday as a "haunting tragedy" sparked by jealousy and wounded ego.

"He was just a young pup in love," Helfand said of Austin. "When it was thrown in his face, he lost it."

But Assistant State's Attorney Robert Dean, who prosecuted the case, said the shooting was a betrayal of trust by an on-duty police officer.

"He was sworn to protect and defend the public," Dean said.

Dean called as a witness yesterday Officer Marquita Jackson, who testified that Austin had told her two days after the shooting that he hoped the incident would spur the police department to buy more powerful handguns for officers.

Jackson quoted Austin as saying, "We should get our 9-millimeters now because I shot him him three times in the head and didn't kill him."

The shooting occurred about 10 p.m. in the stairwell of a Wheaton apartment building, where Austin had gone to meet his girlfriend, Khavah Carter, and Willie Lee Jackson, 22. Austin was accompanied by police officer trainee Brian Holloway.

Jackson, who suffered serious brain damage, testified during Austin's trial that an argument ensued after he told Austin about his relationship with Carter.

Jackson said Austin drove away in his police cruiser after the confrontation.

Holloway testified that Austin then immediately returned to the apartment building and fired four shots at close range at Jackson, striking him three times in the head.

After the shooting, Austin asked Holloway to help dispose of Jackson's body and concoct an alibi, Holloway said.

Austin was arrested when he returned to the Silver Spring police station.