Associated Press

The parents of Columbine High School gunman Eric Harris said in court documents they did not know of his ability to carry out the attack on the school and asked that a lawsuit against them be dismissed.

In a response to claims filed by the family of slain Columbine student Isaiah Shoels, attorneys for Wayne and Kathy Harris also asked the U.S. District Court in Denver to award the Harrises attorneys' fees and other costs.

The response was filed Monday and made available Tuesday

Eric Harris and Dylan Klebold killed 12 students, a teacher and themselves at Columbine on April 20, 1999.

Shoels' parents and several other victims' families have filed lawsuits accusing the Jefferson County Sheriff's Office, Sheriff John Stone, school officials and others of failing to prevent the school shootings and of botching the response. The Harrises have been named in several of the lawsuits.

In Monday's filing, the Harrises denied several claims made by the Shoels family, including an allegation that they knew or should have known about their son's propensity to commit harmful acts.

The Harrises also denied a claim that they "breached their duty of care."

The lawsuit also claims that Harris prepared for the attack for 14 months, which his parents should have seen. The Harrises denied that in Monday's filing.