A New York court viewed surveillance footage which apparently showed a jailed Rod Covlin demonstrating a chokehold on another inmate before he was to stand trial for his wife’s strangulation death.

The footage was reportedly shot in November at the Brooklyn Detention Center’s law library. According to the New York Daily News, prosecutors accused Covlin of bragging about having a black belt; his lawyers claimed he’s a martial arts novice who only took classes as a child.

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Covlin’s currently on trial for the 2009 murder of his estranged wife, Shele Danishefsky. He’s accused of strangling Danishefsky and staging the scene to look like she slipped and fell in the bathtub. Prosecutors believe Covlin, now 46, killed his wealthy wife to gain control of her $5.2 million fortune.

Danishefsky’s death was originally deemed an accidental drowning, as her Orthodox Jewish family requested the coroner didn’t perform an autopsy at her family’s request. Danishefsky’s body was exhumed three months after the slaying—and it was reportedly discovered that her neck had been snapped in two.

The jail footage was accompanied by testimony from Dan Anderson, a martial arts expert who said the hardest part of achieving a chokehold is getting your arm under the other person’s chin.

“The natural response (for the victim) is to bring the chin down,” he explained, according to the Daily News.

Anderson also said Covlin demonstrated a one-armed “bouncer’s chokehold,” which isn’t the professional or proper way the move is performed. The admission, which was made during cross-examination, led the defense to argue that Anderson wasn’t an expert and challenge the validity of his theory.

As the trial comes to a close, defense attorneys claimed prosecutors failed to prove Danishefsky was murdered—placing a bulk of the blame on what they described as “sloppy” police work.

“There’s not one iota of evidence…one single piece of proof that Rod Covlin was inside apartment 515 either on December 30 or December 31 at any time before his daughter called him telling him something was wrong with her mother,” defense attorney Robert Gottlieb told jurors Monday, the Daily News reported.

The prosecution will offer their closing argument Tuesday before the jury undergoes deliberation.

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[Featured Image: Shele Danishefsky Covlin/Handout]