Robert E. Grogg, who authorities said confessed to murdering a construction worker in Northern Virginia because he "didn't like his attitude," was sentenced yesterday to 30 years in prison.

Grogg, 19, pleaded guilty last month in Fairfax County Circuit Court to first-degree murder, robbery and use of a firearm in a felony in the October death of Hallie Hollis, a 28-year-old North Carolina man who worked in the Washington suburbs.

Judge J. Howe Brown yesterday sentenced the Fredericksburg man to 28 years on the murder charge and two years on the gun charge. He also was given a 10-year suspended sentence for the robbery.

Fairfax County Commonwealth's Attorney Robert F. Horan Jr. said that Grogg and his 16-year-old brother Thomas were hitchhiking with two girls on I-95 when Hollis picked them up.

Police officials said in court that Robert Grogg told them that, after stopping for beer, the brothers became annoyed with Hollis. After an argument between the brothers over which of them should pull the trigger, police said, Thomas Grogg fired nine bullets into Hollis' head.

The shooting occurred in the parking lot of Vulcan Material Co., the Lorton rock quarry where Hollis worked.

The brothers took Hollis' car to Florida, where they were arrested, police said.

Officials said Robert Grogg could be eligible for parole in about six years.

Thomas Grogg, who was tried as an adult last month and found guilty of first-degree murder, robbery and use of a firearm, was sentenced last week to 42 years in prison.