HOUSTON – Former Harris County Sheriff's Office investigator Craig Clopton, who was fired over an affair with a key witness in the murder investigation of Deputy Darren Goforth, had his termination upheld during an appeal hearing Thursday.

The Harris County Civil Service Commission decided to deny Clopton's request for reinstatement.

Clopton argued Thursday that he had sex with the witness while he was off-duty, and that he should have been suspended instead of fired.

After the decision, Clopton said, "I have no comment other than to ask for forgiveness to those who I needed to ask. And that's it. I have no other comment."

Prosecutors said Clopton admitted having "consensual sexual conduct" with a witness.

Goforth was shot and killed at a northwest Harris County gas station in August 2015.