"do not in any way allege a violation of our workplace harassment policy," according to the letter.

Tate was accused of misconduct in November of last year after a woman came forward anonymously to KUNC. The state senator has maintained his innocence throughout the investigative process.

After conferring with legal counsel and talking to the vice president of the agency who conducted the independent review into Tate, Grantham concluded the letter by saying he was closing the investigation into his colleague.

"This has been a learning experience for all of us," Grantham said in the letter.

Tate wasn't the only Colorado legislature accused of harassment late last year, as State Rep. Steve Lebsock (D-Thornton) and State Sen. Randy Baumgardner (R-Hot Sulphur Springs) were also accused.

Lebsock was ejected from the Democratically-held state legislatureearlier this year after investigation deemed his accusers credible. Baumgardner has not resigned but did step down as chair of one of the committees he runs in the State Senate after a similar investigation found claims against him credible as well.

At the beginning of the month, Grantham called for criminal investigations into allegations of sexual harassment in the legislature. He wants the District Attorney to look into each claim.

"Anybody that is guilty of sexual assault, if someone is convicted of such a crime or any kind of felony, it is incumbent upon us as a body, a Senate or a House, Democrats or Republicans, to expel those members," said Grantham.

9NEWS talked to Tate’s accuser, who asked us to hide her identity in part out of concern for her