Curl appeared in court in Sycamore, Ill., near DeKalb, via closed circuit TV from jail. He is accused of killing Keller and burning her remains.
Investigators say Curl was arrested in Louisiana last week after failing to appear for a scheduled interview and then fleeing to Mexico. He is being held on a $5 million bond. Curl is charged with five counts of first-degree murder, criminal sexual assault, arson, obstruction of justice and unlawful possession of a motor vehicle in the death of the college freshman. Curl could face the death penalty.
Keller was last seen on October 14 going to Prairie Park where burned remains were discovered two days later. Those remains have not officially been identified as Keller, but items thought to be Keller's, including a cell phone and clothes, were discovered nearby.
In court Monday, Curl's family said he is innocent.
"There's a lot of things that haven't came out. And soon we will get that information... not going to try this in the media but at a later time, maybe," she said. "I truly believe he is innocent. I truly believe that, a lot of things people don't know."
A psychologist has been assigned to Curl per his public defender's request. Curl's next hearing is scheduled for November 30.
"I am not going to comment what the evidence is. There's obviously quite a bit of evidence. Whether or not there was a confession or not, that will come out at the trial," said prosecutor Phil Montgomery.