SPOKANE, Wash. – The suspect in a brutal rape and assault at a Spokane Valley gas station pleaded not guilty to the charges against him Tuesday afternoon.

Michael Rush, a registered level three sex offender, is facing charges of rape, assault, kidnaping and burglary in connection to an attack on a store clerk at the Cenex Zip Trip on East Trent on January 13. A judge set his bond at $750,000.

Spokane County Prosecutor Larry Haskell is working on state's case against Rush. Generally, Haskell only attends first appearances for high profile cases, so that gives you an indication of how serious this one is.

New court documents released Tuesday are also giving more of the awful details into this sadistic crime.

Documents said Rush stopped by the store multiple times that Saturday. Detectives believe he pretended to turn in lottery tickets to see if the clerk was alone around 4:22 a.m. The victim said Rush went to leave the store and returned to shake the victim’s hand, introduced himself and asked if she had a boyfriend. The victim told him she has a boyfriend but he said he would be back at 5:00 a.m. to “get her number” and leaves.

Surveillance video shows Rush walking around the counter, the victim said he told her he had a gun then forced her into the bathroom and closed the door. For the next 30 to 40 minutes, the clerk said Rush violently attacked her, strangled her until she was unconscious and raped her repeatedly. court documents said he ripped the victim’s lanyard off her neck, went through her pockets and took her box knife and EBT food card. Court documents said the rape and assault was so violent the toilet in the bathroom had been broken off the bolts in the floor and moved over by about a foot.

Three customers came into the store, but the victim said Rush threatened to kill her if she made a sound. Documents said Rush pretended to be sick in the bathroom and even told one customer, "Dude, you gotto go, I gotta close the store down because my wife's having kidney failure and I gotta take her to the hospital."

The customer told police he did not see anyone. but said he did hear a woman who sounded like she needed to go to the hospital. One other customer reported hearing moaning but thought Rush was watching a video in the bathroom. When Rush went out to talk to the customer, the victim pressed the panic alarm button on her lanyard and locked the bathroom door.

According to documents, the victim tried to slide her lanyard and sock under the bathroom door in an attempt to attract the attention of the customers but the victim said Rush snatched them up and put them in his pocket before a customer could see it.

While Rush was out of the bathroom, court documents said the victim locked the door to try and keep him out but he broke down the door and continued the assault. Not long after police arrived on scene, called Rush out of the bathroom and arrested him. The victim was able to identify Rush as the person who had raped and assaulted her. Since the attack, the victim said she has returned to the hospital for the blood pooling in her eyes and has had several doctor’s appointments for her eyes, her teeth and a general doctor.

One deputy wrote in court documents that he had “never seen a strangulation victim the severity of (the victim’s) injuries.”

According to court documents, Rush was taken to the hospital after he said he had swallowed meth and heroin. On the way there, documents said Rush said the victim was his wife and someone had beat her up. He said his name was David Spear and claimed a guy on a bike with a Raiders sweatshirt was responsible for the attack. He continued to ask if his wife was ok.

Deputies later discovered Rush had Wenatchee Les Schwab perform labor on his car and left without paying for $1290 in parts. Detectives also searched Rush's phone where they found violent sexual videos and 11 pages of search history for necrophilia.

Rush’s trial has been set for April 2.