In a year that, by any measure, hasn't exactly been slopping over with shining examples of American law enforcement—the profoundly troubled Denver Sheriff's Department may be the least brilliant of them all.

Which means that the last thing they probably needed was yet another one of their deputies getting caught on video beating the hell out of yet another inmate—this time for allegedly daring to mock a deputy's martial arts skills.

According to the Denver Post, Deputy Roberto Roena has been suspended for 90 days for his role in an April 2013 incident in which he kicked an inmate in the head with a sidekick after the inmate allegedly taunted him about his martial arts skills.

Roena was on courthouse duty and was just paying a visit to coworkers at Denver's Downtown Detention Center where he bragged about his sweet taekwondo skills to the officers on duty.

The Post reports that Roena—a 15-year veteran of the department and an alleged adult—then put down a drink and showed off a taekwondo sidekick into the air, which prompted nearby inmate John Cardenas to (rightfully) make fun of him.

That sort of ribbing didn't sit well with the deputy, who then—as shown in surveillance video—kicked Cardenas in the head with a sidekick, followed by a series of punches. Roena then put Cardenas in a headlock and the two tumbled to the ground before other deputies jumped in to break up the fight.

The high-kickin' deputy—apparently unaware of how video works—claimed self-defense and that he was defending himself from attack by Cardenas, who had a jailhouse reputation for violence but had not actually showed any physical aggression to Roena or the other deputies.

In his letter of reprimand, investigators say that Roena made a very bad decision indeed.

"At the time of the initial interaction, inmate Cardenas posed no objectively reasonable threat to Deputy Roena's safety," the letter said. "It was only after Deputy Roena's poor decision to engage inmate Cardenas that inmate Cardenas demonstrated potentially physically aggressive behavior."

According to the Post, in a disciplinary meeting with officials months after the incident, Roena finally agreed that a cell block in the city jail probably wasn't the best location for a martial arts demonstration.

In the end, it took a shocking 15 months from the time of the incident for city officials to finally discipline Roena for his actions.

This jailhouse martial arts showdown is just the latest in a series of high-profile, deeply embarrassing and very expensive incidents that has prompted Denver officials to finally try and clean up the sheriff's department.

Earlier this year, the city had to pay out $3.25 million to former inmate Jamal Hunter, who in 2011 was grabbed by the neck, choked, beaten and kicked by Deputy Edward Keller while he was being booked at the Downtown Detention Center.

The Hunter case led to the resignation of Sheriff Gary Wilson and a review of the entire department ordered by Mayor Michael Hancock. In addition, a judge has also called for a federal investigation into the department after allegations that officers tried to intimidate a witness in the Hunter case.

That witness, inmate Amos Page, alleges that deputies essentially let him run that Detention Center pod and he would routinely assault other prisoners under orders of deputies. He claimed that he witnessed the Hunter assault, and was warned by department investigators that if he testified he would be implicating himself in a crime.

In another incident also captured on video from this past July, an inmate who was being booked at the facility was punched and kicked by Deputy Thomas Ford. According to investigators, the inmate was being verbally abusive to deputies, but had not actually displayed any physically aggressive moves towards anybody when he was attacked.

Both Keller and Ford—who was also involved in the Hunter case—were finally fired this past week for using excessive force and then lying about their actions on official incident reports.

Keller's attorney says that his client intends to appeal.

And it looks like things could get a lot worse for the beleaguered Denver Sheriff's Department, as a recent Denver Post investigation has uncovered another 45 inmate complaints on file alleging abuse by deputies that have not been investigated by the department.

Image via Denver Sheriff's Department.