The head of the Victoria Police integrity unit has been ordered to take leave after admitting he made a fake Facebook profile under the name “Vernon Demerest” and used it to make inappropriate remarks about the former police commissioner Christine Nixon.

Brett Guerin, the assistant commissioner for professional standards, said he was “embarrassed” by his actions, which also included disparaging comments about the former police association president Paul Mullett and the former chief commissioner Kel Glare.

“For the head of ethical standards to be trolling over a period is really beyond belief,” Glare told Fairfax Media.

Guerin told radio station 3AW on Thursday he had embarrassed himself.

“I’m embarrassed about it, I’ve humiliated myself by doing it,” he said. “This has been a big learning experience for me. Which is what we want our members to do, we want our members if they make mistakes to own up and make amends so they get better.”

The incident was referred to Victoria’s Independent Broad-based Anti-Corruption Commission (IBAC) on Wednesday.

The chief commissioner, Graham Ashton, said on Friday that he had directed Guerin to step aside as assistant commissioner for professional standards and take leave.

“As the matter is now with IBAC for its consideration, it would not be appropriate to comment further,” a police spokesman said.

The pseudonym “Vernon Demerest” is a reference to a character played by Dean Martin in the 1970 movie Airport. Demerest is the pilot who tries to calm down a bomber threatening to blow up the plane.

Guerin used the pseudonym to comment on the post of a Sydney shock jock who had been sued by Nixon, writing in August 2016: “Master fisherwoman Chrissy just gutted him and stuffed a nice prawn up his filleted asshole”.

Guerin had been Nixon’s chief of staff at the time, and said he was defending her.

He told 3AW he did not believe he had breached police ethical standards but said he had “dropped the ball” and was ashamed that his mother and daughters had read the comments.