CARBON COUNTY, Utah -- Police in Carbon County have arrested a man who is accused of fatally shooting his mother and younger brother at a ranch several miles outside the ghost town of Hiawatha.

According to the Carbon County Sheriff's Office, the shooting occurred around 6 p.m. at a ranch near Hiawatha, which is a ghost town about 12 miles southwest of Price.

The sheriff's office has identified the victims: 45-year-old Susan Peterson and 23-year-old James Peterson.

Police said 25-year-old Seth Gordon Peterson was arrested in connection with the shooting after he fled from police at high speeds for about 5 miles before eventually surrendering peacefully. Seth is Susan's son and James' older brother.

Seth is facing multiple charges including two counts of aggravated murder, one count of attempted murder, car theft and failure to stop at officers' commands.

Authorities said two people witnessed the shooting and reported seeing the suspect shoot the pair with a high-powered rifle.

"They attest to Seth shooting the gun and killing the two victims," said Whitney Waterfall, the Carbon County Emergency Management Specialist.

According to a news release from the Carbon County Sheriff's Office, a motive has not been established. It was not clear why the family members were at the ranch were the shooting occurred.

"We know the property owners of this home, but we don’t know the correlation, if there is a family dynamic or not," Waterfall said.

The Peterson family released a statement through their LDS Bishop, saying Susan was a loving mother of 15 children and James was kind-hearted and the kind of person to give someone the shirt off his back. A GoFundMe account has been set up to assist the family. See below for the full statement:

"Susan was a loving mother of 15 children, ages 28 to 3. She was very active in the community and in her church. Susan was very service oriented and was always taking care of other people. She was a very intelligent person, always thirsting for knowledge in bettering herself and her family. Her family was her whole life and she supported them in all they did. Susan always thought of others before herself. Her husband states that she would often go without new clothing and other necessities in order to make sure her children had what they needed. She never wanted for herself. James was kind-hearted and would give you the shirt off his back. He was very personable, kind, respectful and thoughtful of others."