Each was arraigned on a captial murder charge at the Conway County Courthouse Friday afternoon, officials said.
Earlier this week, Chauncey and Barr were charged in Tuesday's attack on two women and their mother in the nearby town of Conway, Ark., according to police.
The capital murder charges filed against Chauncey and Barr stem from the shooting death of truck driver Arthur Joe Cotton at a rest area along Interstate 40 near Morrilton, about 40 miles northwest of Little Rock, according to Conway County Circuit Court records.
According to Arkansas authorities, Cotton was on his way home from Tulsa, Okla. He was delivering gravel on a trucking route when he pulled over to a rest stop.
Two men allegedly approached Cotton and asked him for money.
Conway County Sheriff's deputies responded to the rest area about 8:37 p.m. on Jan. 30 after receiving a call that a body had been found in one of the men's restroom stalls, according to court records.
Investigators determined the man had been shot once in the left temple, court records said. They found a spent .45-caliber shell casing in the victim's hat, which had been knocked to the floor between the victim's body and the wall of the toilet stall, court records said.
The 71-year-old truck driver should have been carrying about $200 in cash, but there was no money in the man's wallet, according to court records.
``I feel angry,'' said Cotton's son-in-law, Jim Brewer, who sat glaring at the two men in the courtroom on Friday. ``He was the nicest, most trusting person you could meet. They had to be real cold-hearted to do what they did.''
Barr and Chauncey answered investigators' questions about the Jan. 30 slaying from the Faulkner County Detention Center in Conway, where they have been held since their arrest in this week's rapes and the attack in Conway.
According to court records, Barr told police that he and his brother arrived separately at a rest area along I-40 - with Barr driving a 1976 blue Ford pick-up truck and Chauncey driving a white Ford Explorer which they had stolen from a car lot in West Virginia.
Investigators said a Ford Explorer - taken from the Kent Parsons Ford dealership near Martinsburg on Jan. 22 - had fled police after the rapes in Conway.
During Friday's arraignment, Jerry Don Ramey, prosecuting attorney for the 15th Arkansas Judicial District, requested the death penalty should Barr and Chauncey be convicted, said Circuit Court Clerk Carolyn Gadberry.
Gadberry said the death-penalty request is expected to be discussed during a probable cause hearing for the brothers on Feb. 26.
During the arraignment Friday, Barr and Chauncey were found to be indigent, and a public defender was appointed for each, Gadberry said. After the hearing, the brothers returned to the Faulkner County Detention Center, where they are being held without bond, Gadberry said.
The attack on the mother and daughters in Conway and the slaying near Morrilton have frightened residents in the two small towns, and police said they are trying to determine if the brothers are linked to other crimes, such as unsolved slayings in Tennessee and Oklahoma.
Gadberry said the slaying of the truck driver is the ninth capital murder cases pending in her district. "It's hit everyone here," said Gadberry.
A Berkeley Springs police officer and a local high school counselor who knew Barr said he was a polite person who had potential.
But a counselor at Berkeley Springs High School said Barr also had personal problems, and while he was in school, he was enrolled in an adult tutor program that is designed to help kids with a variety of problems from homework difficulties to a lack of an adult role model.
- The Associated Press contributed to this report.