A Washington police sergeant has been arrested for allegedly sexually assaulting an Washington State University student.

A sergeant with the Pullman Police Department has been arrested on first-degree custodial sexual misconduct charges involving an intoxicated university student.

Pullman cop Jerry Daniel Hargraves, 49, was arrested Tuesday morning after an investigation that began in April when the freshman student at Washington State University who reported she was sexually assaulted by officer Hargraves when she was intoxicated back in March.

According to court documents, the student had contact with Pullman police on three separate occasions regarding underage drinking on the night March 30.

The victim was "staggering and appeared intoxicated," according to court documents.

Although she'd been warned previously twice to stay inside her dorm, the student left again "to meet up with friends."

Hargraves, along with another officer, made contact with the victim and scolded her after arriving again.

"You disobeyed me," Hargraves told the 18-year-old student.

"I told you to not leave your dorm before. Now I have to take you to the station because you didn't obey my orders," he threatened the student.

Hargraves did not handcuff the student, but placed her in the back of his patrol car and began driving around.

"I'll do anything to not get arrested," court documents say the victim told Hargraves.

"What are you willing to do?" he replied.

The victim replied saying she would "have to pay him a good sum of money" and that she would do "like anything," documents say.

The victim told detectives the vehicle "became very quiet and Hargraves stopped a few minutes later" near a park.

Hargraves "instructed her to get out and get down on her knees" and the victim "remembered hearing him undo his pants."

The victim reported to investigators that she had a "vague recollection of performing oral sex on Hargraves" and said she later wiped her face with her sleeve after the act.

At that point, Hargraves told the victim to get back in the car and asked her where she wanted him to drop her off and he later dropped her off at Rogers Hall.

Then, less than a week later on April 5, she called the Officer for Equal Opportunities to report the incident.

Washington State Patrol investigators swabbed both officers' cars on April 9 and found no DNA evidence inside their vehicles and no evidence regarding the incident was found on their cell phones.

On April 18, detectives interviewed the victim again and "she provided details and a timeline as well as identifying Hargraves as the officer that made her perform a sexual act" documents reveal.

Later, the victim also provided investigators with the clothing she wore the night of the assault and it was sent off to the Washington State Patrol Crime Laboratory for DNA testing.

On June 11, a forensic scientist from the Washington State Patrol "located sperm on the sleeve of the victim's clothing" and the next day detectives got a search warrant to test Hargraves' DNA and later obtained a sample.

On August 14, the forensic scientist discovered DNA on the victim's clothing was a match with Hargraves' DNA sample.

"I want to comments the WSU student who came forward to report this. It takes a lot of courage to do that, especially against a law enforcement officer," Pullman Police Chief Gary Jenkins said during a press conference about the incident, which can be viewed below.

"We stand here acknowledging that there was a failing in our department and that we know that our people have to be held to a high standard of conduct," he said.

"And so because of that, we do hold our people accountable. And so we think . . . we believe that a lot of work we’ve done in our community, and the way the community knows us, they know as a department they can trust us. Moving forward, we will continue forward to earn that trust."

The victim no longer attends Washington State University, Jenkins told reporters.

Sergeant Hargraves worked 19 years for the Pullman Police Department and has been a sergeant for 14 years.

Hargraves was placed on administrative leave after the allegation was reported.

He was the subject of a previous internal affairs investigation for sending inappropriate text messages to a female employee of the Pullman Police Department in 2016.

For the incident, the department mandated Hargraves undergo counseling, according to the Spokesman.