Jessica Ridgeway Case: Austin Sigg confessed to slaying of 10-year-old Colo. girl, prosecutors say

(CBS/AP) GOLDEN, Colo. - Prosecutors say Colorado teenager Austin Sigg confessed to the abduction and killing of 10-year-old Jessica Ridgeway and a separate attack on a jogger.

Pictures: Body of 10-year-old Colo. girl found

According to CBS Denver, prosecutors said at Sigg's first court appearance Thursday that he will be tried as and adult. He was ordered held without bond.

Authorities also said Thursday they have "overwhelming" DNA evidence against 17-year-old Sigg.

Westminster police said they took the Arapahoe Community College student into custody Tuesday night after receiving a phone call that led them to him.

"I made the phone call, and he turned himself in. That's all I have to say," Mindy Sigg, his mother, told The Associated Press on the phone before she broke down in tears and hung up.

Sigg student lived about a mile from Jessica, who disappeared on Oct. 5 while walking to Witt Elementary School. Her remains, which authorities said weren't intact, were found five days later.

Authorities said Austin will also face charges in the May 28 attempted kidnapping of a 22-year-old runner at the Ketner Lake Open Space. A woman reportedly fought off a stranger who grabbed her from behind and put a rag that smelled of chemicals over her mouth.

Relatives of Ridgeway were in the courtroom Thursday wearing purple ribbons in the girl's memory.

Complete coverage of Jessica Ridgeway on Crimesider