Updated

A search that set parents in the Denver area on edge last fall, had neighbors casting a suspicious eye on neighbors, and left a family grieving the loss of a 10-year-old ended with the teen suspect telling a 911 dispatcher: "I murdered Jessica Ridgeway. I have proof that I did it."

He told the 911 dispatcher that some of Jessica's remains were in the crawl space at his mother's house, according to a recording of the Oct. 23 call played in court during his preliminary hearing Friday. Fifth-grader Jessica disappeared Oct. 5 after she left her house to meet a schoolmate two blocks away so they could walk to school together.

A judge ordered Austin Sigg, 18, to stand trial and be held without bail for Jessica's slaying and a May attack on a jogger at Ketner Lake, which is across the street from Jessica's elementary school. In the attack on the jogger, investigator Michael Lynch testified that Sigg used homemade chloroform concocted with a recipe found on the Internet to attempt to subdue a woman.

Lynch testified at the hearing that Sigg first confessed to his mother, telling her that he kidnapped Jessica as she walked past his car, bound her arms and her legs with zip ties, placed her in the back seat, drove around for a little bit, then took her to his house.

He tried to strangle her, first with zip ties and later with his hands, Lynch testified. He later dismembered her, he said.

Sigg, now 18, is charged with murder, kidnapping, sexual assault and robbery in Jessica's death. Prosecutors have added three counts of sexual exploitation of a child because child pornography was allegedly found during the investigation.

He also faces an attempted kidnapping charge for the attack on the jogger. An attempted murder charge was dropped by prosecutors and the judge found there wasn't enough evidence for an attempted sexual assault charge in that case.

Hundreds of officers canvassed the area after Jessica's disappearance, investigated leads and took DNA samples as parents waited with their children at bus stops and thought twice about letting them out of sight. The FBI took the unusual step of asking residents to observe their family members and neighbors for suspicious behavior.

One of those residents contacted authorities Oct. 19 to report Austin Sigg because of his fascination with death, Westminster Detective Luis Lopez testified. Two FBI agents responded and took a DNA sample from Sigg on Oct. 19, four days before his mother called 911.

Lopez testified that Sigg attended a community college because of their mortuary sciences program.

Mindy Sigg told Lynch her son appeared sick and confessed, four days after the visit from the FBI, opening the conversation by saying he was a "monster."

Mindy Sigg then called 911 to say her son wanted to turn himself in and had confessed to killing the girl. When the dispatcher asked what her son had said, Mindy Sigg replied, "That he did it, and he gave me details, and her remains are in my house."

She can be heard crying and asking if her son will talk to the dispatcher, who asks him general questions.

"I don't exactly get why you're asking me these questions. I murdered Jessica Ridgeway. I have proof that I did it," Austin Sigg said. "You have to send a squad car down here, and I'll answer any questions you want to ask me."

He also said the remains were in a crawl space.

When asked about his criminal record, he told the dispatcher: "The only other thing that I have done was the Ketner Lake incident where the woman got attacked. That was me."

Both Mindy Sigg and Austin Sigg wiped their faces with tissue as the tape was played. Jessica's mother and other family members looked down.

Lopez said Sigg's DNA -- the kind left behind by touching something -- was found on Jessica's clothing, but no semen was found.

Sigg told investigators that he didn't rape Jessica, Lynch said.

"It was a comment he had made right off the bat, `I didn't rape her. I didn't torture her."'

Some of Jessica's remains were found in garbage bags in an open space park five days after she went missing. Friday was the first time investigators revealed that the bags contained her torso. Lopez testified that she died of asphyxiation.

The judge originally ordered Friday's hearing to be closed to the public but the Colorado Supreme Court sided with media organizations who argued that he failed to show that holding the hearing in public would jeopardize Sigg's right to a fair trial.

Arraignment, where Sigg is to enter a plea, is set for March 12.