Prosecutors in court said they have a confession and DNA tying a 17-year-old college student to the kidnapping and murder of Jessica Ridgeway after sources tell ABC News that human remains were found at his home in Westminster, Colo.
Austin Reed Sigg made his first court appearance in Jefferson County Court Thursday, one day after he was arrested and charged with two counts of first-degree murder, one count of second-degree kidnapping and two counts of criminal attempts.
Prosecutors said that Sigg's DNA was on Ridgeway's backpack and at the crime scene in the Arvada, Colo., where her body was found Oct. 10. Lawyers also said that traces of Sigg's DNA were left at a crime scene involving a jogger who was attacked in May.
Sources tell ABC News that human remains believed to be Ridgeway's were found inside his home, which is less than a mile away from where the 10-year-old lived with her mother. Investigators have been searching for clues in Sigg's home since his arrest. Sigg shares the home with his mother, Mindy.
"Austin functions on a different reality, perhaps, than the rest of us. The idea that he has partial remains at his house may be excitement, may be adventure, may be sexual," former FBI agent and ABC News consultant Brad Garrett said.
Sigg was arrested Wednesday after confessing to his mother, who then called police so her son could turn himself in, sources told ABC News on Thursday.
Now Sigg's public defenders will plot their legal strategy.
"The defense attorneys will point to both procedural error and will try to undercut the reliability of DNA evidence," Cole said.
Though Sigg will be tried as an adult, if convicted, he is not eligible for the death penalty or for a mandatory life sentence without parole, under Colorado law. Sigg has not entered a plea.
Cameras and sketches were not allowed inside the court on Thursday, but ABC News producer Philip Maravilla sat behind Ridgeway's family. The family was dressed in pink, which was Jessica's favorite color.
The Ridgeway family did not interact with Sigg's family, according to Maravilla, who said he didn't see any eye contact between the two families.
"[The Ridgeway's] seemed to not have any animosity toward the Sigg group. On the Sigg side, I could hear some weeping," Maravilla said.
Sigg is a student at Arapahoe Community College Littleton, Colo., according to his arrest report, where classmates said he was studying mortuary science. He took second place in a high school competition involving crime-scene investigations.
Fellow classmates at college said Sigg made them feel uneasy.
"I thought that he was very intelligent. I just thought that he had that pale… dark eyes… I don't know. I can't explain it. It's just creepy," said classmate Jacqueline Miller.
Sigg's parents are divorced, but his father, Rob, released a statement overnight.
"There are no words to express the sorrow that I and my family feel for their pain they are suffering" his statement said. "I ask also for your prayers and support for Austin's mother, whose courageous act … unimaginably painful for any parent … has put this tragedy on the path to resolution.