(CBS/AP) WESTMINSTER, Colo. - Austin Sigg, a Colorado teen due in court today in connection with the death of 10-year-old Jessica Ridgeway, confessed to the murder, prosecutors say. He is also accused of a separate attack on a runner earlier this year, authorities said.
Westminster police said they took Sigg, 17, 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.
The Arapahoe Community College 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. Police said the two crimes are connected but haven't elaborated, and they haven't determined if the substance on the rag was meant to subdue the runner.
Authorities released few details about their investigation, and court documents are sealed. A police custody report said Austin was cooperative when he was arrested and waived his rights.
Austin attended Witt Elementary, but moved on to middle school in 2007 before Jessica enrolled at Witt, Jefferson County Public Schools spokeswoman Lynn Setzer said. He later attended Standley Lake High School while also taking classes at Warren Tech, a district school that offers specialized training in health science, public safety, technology and other fields.
He left the school district in July after finishing the 11th grade and later earned a GED. School officials don't know why he left.
Former high school classmates described Austin as an intelligent teen who often wore black and complained about school but who would stay late sometimes to work on computers.
"It's just so weird to grasp the concept of how, like, I knew him and how he lives so close to us," said Standley Lake alumna Rachel Bradley. "I never saw it coming,"
Bradley, 17, said Austin was interested in mortuary science and was taking forensics classes. Arapahoe Community College offers the state's only accredited mortuary science program.
Standley Lake alumnus Dakota Foster said he and his friends sat at the opposite end of a cafeteria table from Sigg and his friends.
"He was really nice and laughed a lot with us and told jokes, and laughed at our jokes," Foster said.
Foster, 19, said he didn't know Austin well, but "he used to hang out with a lot of us in what we called the goth corner (of the school cafeteria), where all the metal heads were."
"He wore all black so he fit in," Foster said. He added he wasn't surprised that Austin left high school after the 11th grade, as Austin always complained about school and didn't like his classes very much.
Police said they notified the Ridgeway family of the arrest Wednesday morning. Jessica lived in Westminster with her mother, Sarah Ridgeway. Jessica's father, Jeremiah Bryant, lives in Missouri.
Jessica's great-grandmother Donna Moss reportedly said she feels for Austin's mother but has to fight the rage she has toward Austin because she knows as a Christian she should forgive.
"I think it's all I've got within me to not want to just burn him, and I mean burn him," she said.
The arrest brought some relief to the community, where some parents said they were nervous about letting their children play outside as authorities searched for Jessica's killer.
"Every parent in every Colorado community will rest a little easier tonight," said Gov. John Hickenlooper. "While we still mourn the death of Jessica Ridgeway, we are relieved an arrest has been made and the pursuit of justice can continue."