GOLDEN, Colo. (AP) -- A teenager accused of kidnapping and killing a 10-year-old Colorado girl and attacking a runner will be prosecuted as an adult.

The judge presiding at a hearing for 17-year-old Austin Sigg Tuesday said the defense had waived its right try to move the case to juvenile court. Prosecutors charged Sigg as an adult last month but Sigg's lawyers had the option of asking Judge Stephen Munsinger to move the case to juvenile court.

Munsinger also agreed to move Sigg to adult jail at the request of the state's juvenile justice system. Officials said Sigg is being held in an isolation cell not meant for long-term stays and requires full-time supervision.

Sigg turns 18 in January and Munsinger noted that he would have been moved to adult jail after that anyway.