A man accused of kidnapping and sexually assaulting a young girl at the Lone Tree Library will spend the rest of his life behind bars.

Scott James Sylvia, 27, was sentenced by a Douglas County District Court judge Sept. 3 to 336 years to life in prison for the 2008 assault in the parking lot of the library. Sylvia was found guilty June 9 of kidnapping, sexual assault, aggravated robbery, first-degree criminal trespass, two counts of second-degree assault and retaliation against a witness or victim.

In a tersely worded overview of the case during the sentencing hearing, presiding judge Paul A. King called Sylvia’s actions against the victim “unimaginable.”

“The crime that you committed on the victim was brutal,” he said. “I cannot imagine the horror she must have felt when you sexually assaulted her, Mr. Sylvia.”

Sylvia pleaded not guilty by reason of insanity to all charges. The jury found that the prosecution proved his guilt and his sanity beyond a reasonable doubt, a press release from the 18th Judicial District Attorney’s office says.

Sylvia attacked the victim, who was not identified by authorities, in the parking lot as she was leaving after checking out a book July 7, 2008. He was apprehended by the Lone Tree Police Department five days later after he was identified by the victim from the library surveillance cameras and DNA from the scene.

Prosecutors credited the Lone Tree police detectives for their tireless efforts in solving the case. Sylvia was quickly arrested “due to their diligence in pursuing every lead,” the DA’s office said.

He appeared in a Castle Rock courtroom for the sentencing and was immediately remanded into custody. It is unclear where Sylvia will serve his sentence.