Zachariah Blanton, 18, of Gaston, had been scheduled to stand trial next week on charges of murder, attempted murder and criminal recklessness. He pleaded guilty in Jackson Circuit Court to lesser charges of voluntary manslaughter with a deadly weapon and criminal recklessness.

A judge must still approve Blanton's deal with prosecutors. Sentencing is set for Dec. 27, and Blanton could receive anything between 20 years and 50 years in prison.

Prosecutors say Blanton fired his hunting rifle into highway traffic from an overpass about 60 miles south of Indianapolis on July 23, 2006.

One of the shots went through a pickup truck's windshield and killed 40-year-old Jerry L. Ross. An Iowa man traveling in another pickup truck was injured.

Police say Blanton later shot at cars along another highway northeast of Indianapolis, but no one was injured. Blanton, who was 17 at the time, was arrested at his home two days later.

Blanton's defense attorney did not publicly comment after court and did not immediately return a phone call.

Blanton confessed to the shooting and provided police with details, police have said. Blanton told police he fired the shots to relieve pressure after he argued with fellow participants in a southern Indiana hunting trip. Blanton confirmed the motive in court Monday.

Ross's relatives, wearing "Justice for Jerry" buttons outside the courthouse, said they were unhappy with the deal.

His father, 70-year-old Jesse Ross, said a jury should decide Blanton's fate.

"Twelve people would be about as fair as it could be, it couldn't get no better than that," he said. "I don't think this is right, the way they're doing it. All we want is a fair trial because you can't bring nothing back."

Blanton "committed those crimes, he should be standing trial for them," said Jerry's twin brother, Terry Ross, who was in the truck with his brother when he was shot. "He didn't give Jerry any kind of a deal."

Prosecutor Rick Poynter said he had to make the deal based on the strength of his case. He noted that the judge had ruled that statements Blanton gave police were inadmissible.

If Blanton had been convicted of murder, he could have faced 45 to 65 years in prison. But Poynter said the jury also could have acquitted him or found him guilty of reckless homicide, a lesser crime punishable by two to eight years in prison.

Poynter said that although he understood the family's reaction, "I think they would be a lot more emotional if the killer of their loved one walked out of jail in four years."