A man accused of sexually assaulting and murdering an 18-year-old Moore High School student could face the death penalty.Warning: Some of the details in the story below are disturbing.Court documents filed by the state describe the murder of 18-year-old Madeline Bills as "especially heinous, atrocious or cruel." Cleveland County District Attorney Greg Mashburn says that's why the suspect, Chace Cook, should face the death penalty."In these times, it's always sad when you have a crime like this one that has occurred," Moore Police Lt. Wes Yost said in April after Bills' body was found. "Our thoughts and prayers go out to her family and her friends, and we want to make sure we're doing everything we can to find justice for Madeline."| MORE | Cleveland County DA seeks death penalty for man charged with rape, murder of Madeline Bills In late April, Moore police responded to a home where Bills was found dead in her bedroom. Investigators arrested Cook, her ex-boyfriend.Court documents show that Cook's phone had videos of him and Bills the night of her death. Some of the videos show Cook assaulting Bills while she was unconscious.Mashburn now says Cook should be put to death for what he's accused of doing, saying the murder was atrocious and that Cook could be violent and a threat to society.Bills' family released a statement, saying they continue to grieve the loss of their daughter and that they want to thank those pursuing justice. They added that they support the decision to seek the death penalty.| MORE | Is the evidence enough to convict accused rapist, murderer in Cleveland County?"We wish to express our gratitude to District Attorney Greg Mashburn and his office for their tireless efforts in pursuing justice for Maddie," the Bills family wrote in the statement. "We fully support their decision to seek the death penalty for the defendant. We believe that this is an appropriate sentence given the heinous nature of the crime and the devastating impact on our family and community."Cook's next court appearance is scheduled for 9 a.m. Feb. 28.Top Headlines TIMELINE: Wintry mix to bring snow, arctic front to Oklahoma late Thursday, early Friday Chesapeake Energy announces merger with Houston-based company Investigation underway after person shot, killed outside Beckham County oilfield business WATCH: High school robotics team finishes first prototype of wheelchair for a pup named Roo Rossen Reports: Here’s where travel prices are dropping right now