Colton Harvey, Ark. teen, sentenced to 45 years after pleading guilty in sister's shooting death

(CBS/AP) RUSSELLVILLE, Ark. - A 15-year-old boy accused of shooting his older sister three times in the head as she slept at their rural Arkansas home pleaded guilty Wednesday to second-degree murder in exchange for a 45-year prison term.

Colton Harvey was charged as an adult in the January killing of 16-year-old Candace Harvey. Prosecutors said Candace was asleep in her bed when her brother fired the shots.

Judge William Pearson sentenced Harvey to 30 years for second-degree murder plus 15 more because he used a gun. Prosecutors initially charged Harvey with first-degree murder, which has a maximum penalty of life in prison.

Authorities said Harvey likely killed his sister one January morning after their parents left to go grocery shopping about 40 miles away. The sheriff said he seemed remorseful and had tears in his eyes when he turned himself in that same morning.

Investigators found his sister's body in a bedroom at the family's home near Ozark, a town of about 3,600 roughly 120 miles northwest of Little Rock.

The question of why Harvey shot his sister remains unanswered.

"He never did give what I would consider to be a clear motive," prosecutor David Gibbons said after the hearing.

Harvey's attorney, Bill James, pointed out that there's a history of mental illness in Harvey's family but said that an expert wasn't able to give him a diagnosis because of his age.

"Every time I've ever seen him, he's cried," James said. "And it's not, 'Woe is me.' It's about what he's done to his mom and what he's done to his family."