The College Football Live crew breaks down the advantages of the Arizona job as well as candidates like Kevin Sumlin who would be a good fit in Tucson. (2:15)

The Arizona Wildcats on Tuesday fired football coach Rich Rodriguez after six seasons in the wake of a sexual harassment allegation the university began investigating in October and a recent notice of a hostile-workplace lawsuit to be filed against Rodriguez.

"After conducting a thorough evaluation of our football program and its leadership, both on and off the field, President [Robert] Robbins and I feel it is in the best interest of the University of Arizona and our athletics department to go in a new direction," athletic director Dave Heeke said in a statement.

In a letter to the Arizona community, Heeke and Robbins said Arizona's Office of Institutional Equity retained the law firm of Cohen Dowd Quigley to investigate the allegation, which was made by the former administrative assistant to the 54-year-old Rodriguez. ESPN generally does not identify a person who has reported sexual harassment.

After the investigation began, the former employee hired an attorney and declined multiple requests to participate in the investigation into her allegation and was "unwilling to turn over communications that she alleged provided support for her allegations," the letter stated.

The investigation, which concluded Dec. 28, determined the allegation could not be substantiated, but, according to Heeke and Robbins, "Arizona Athletics did become aware of information, both before and during the investigation, which caused it to be concerned with the direction and climate of the football program.

"As a result, we have been reviewing the finding and deliberating our course of action. While this is a difficult decision, it is the right decision. And it is a decision that lives up to the core values of the University of Arizona."

Rich Rodriguez, who went 43-35 in his six seasons at Arizona, said he was "very excited about the trajectory of our young team, and looked forward to 2018 and beyond." James Snook/USA TODAY Sports

Rodriguez issued a statement Tuesday night saying he found out about his firing by email. In the statement, he admitted to having an extramarital affair with someone not affiliated with the university, but Rodriguez denied any allegations of harassment. He also said the former employee threatened a $7.5 million lawsuit against him.

"The University initiated a thorough outside investigation. I fully cooperated with the investigation, including voluntarily taking and passing a polygraph," Rodriguez said. "The University determined that there was no truth to her accusations and found me innocent of any wrongdoing.

"This was a thorough investigation that lasted over 10 weeks and included multiple members of my current and former staff. Notably, the complainant refused to cooperate with the investigation. It was comforting to be reassured of what I already knew, the claims were baseless and false."

The former employee on Thursday filed a $7.5 million notice of claim with the state's attorney general's office alleging Rodriguez ran a hostile workplace. A notice of claim is a legal document that signals a lawsuit will be filed.

According to a copy of the notice of claim obtained by ESPN, the woman says Rodriguez forced her to keep his extramarital affair a secret while also groping and attempting to kiss her among other actions that made the woman uncomfortable.

The claim includes an allegation that players on the team sent the woman screenshots of their genitalia and illicit overtures via text message and that when she went to Rodriguez to intervene, he ignored her.

After a January 2017 incident during which the woman alleged Rodriguez "touched the side of her breast and tried to kiss her," he offered her $300 and "begged" her not to tell her husband or his wife about the incident, but she declined to take the money.

The university said it would honor the separation terms of Rodriguez's contract, which was set to run through May 31, 2020. Arizona is required to pay 100 percent of what remains on what it refers to as his "university-funded compensation" -- an amount that totals $5.46 million.

Arizona will hire a search firm to assist with "a national search" to find a new coach.

"We'll move through the coaching search in an effort to identify a head coach that will build a solid foundation for our program and create an identity of Arizona football that the University, Tucson and Southern Arizona communities can be proud of," Heeke said in the statement. "We're excited about the future of our football program and we look forward to introducing our new head coach at the completion of the search process."

Rodriguez guided the Wildcats to a 6-2 start in 2017 before finishing 7-6, losing 38-35 to Purdue in the Foster Farms Holiday Bowl on Dec. 27.

Overall, he went 43-35 at Arizona, averaging less than six wins over the past three seasons. Before joining the Wildcats, he coached at Michigan in 2008-10 (15-22) and West Virginia in 2001-07 (60-26).

Rodriguez took the Wildcats to five bowl games during his tenure, including the 2014 Fiesta Bowl. Before his arrival, Arizona reached only three bowl games in 13 seasons.

"My coaching staff and I were very excited about the trajectory of our young team, and looked forward to 2018 and beyond," Rodriguez said in his statement. "... To my players, staff and supporters, it's been an honor to lead and serve you. As I'm sure that you would expect me to do, I will vigorously fight these fabricated and groundless claims.

"... I am not a perfect man, but the claims by my former assistant are simply not true and her demands for a financial settlement are outrageous. I am saddened that these accusations and investigation have caused my family additional stress."

As of Tuesday, with the firing of Rodriguez, the Pac-12 will have five new football coaches when the 2018 season begins. Arizona State, Oregon, Oregon State and UCLA have also made moves this offseason.

Information from The Associated Press was used in this report.