Updated

A 15-year-old boy who allegedly showed up at an Arkansas sheriff's office last week to say he had just killed his older sister was formally charged Wednesday in her fatal shooting.

Colton Harvey is charged as an adult with first-degree murder in the Jan. 15 slaying of his 16-year-old sister, Candace, who was found shot to death in a bedroom in the family's home near Ozark, a rural community about 120 miles northwest of Little Rock. If convicted, he could be sent to prison for life.

The teen's parents, who investigators say were grocery shopping 40 miles away on the morning of the shooting, apparently have not commented publicly about the case and did not respond to a phone message left Wednesday at their home.

Judge William Pearson last week ordered that a public defender be assigned to represent Harvey, but none was listed in the charging documents. The public defender responsible for assigning cases did not return a phone call, and Franklin County prosecutor David Gibbons said he didn't know who was representing the boy.

Pearson ordered Harvey held on $750,000 bail and scheduled his next court date for March 1. It wasn't clear Wednesday whether the boy's bail had been paid or where he was being held. Boen had said Harvey was placed in a juvenile detention center after he confessed, but the sheriff did not immediately respond to a call Wednesday seeking further information.

Sheriff Anthony Boen said Harvey showed up at his office on the morning of the shooting with tears in his eyes and confessed to killing his sister.

"He just said that he had just shot and killed his sister," Boen said. "... He didn't give a motive."

Authorities said Candace Harvey was found shot to death in one of the bedrooms, but have not said how many times or where on her body she was shot and the autopsy results hadn't been made public as of Wednesday.

Authorities confiscated multiple guns from the family's home and vehicle, and were trying to determine which weapon had been used. The sheriff said the boy and his father were avid hunters.

___

Follow Jeannie Nuss at http://twitter.com/jeannienuss