In “The Sparring Partner,” the sadistic Henry (Yeung Wai-leun) is accused of conspiring to kill his parents with his slovenly friend Angus (Mak Pui-tung). Most of the movie represents their court trial through interviews conducted both in and outside of court. Henry’s guilt seems to be assured, given his unbothered body language and unrepentant testimony. His motives also seem clear: he might have done it for his parents’ real estate, because he was jealous of his older brother, or maybe because of his sociopathic admiration for Hitler. Henry’s delusional is what I’m saying, and everybody, including his trial’s nine jurors—two more than usual—already seem to know who he is.

Angus isn’t as easy to pathologize. The evidence against him is flimsy, and his mental and emotional intelligence is often questioned. However, many hints throughout “The Sparring Partner” suggest that the terms by which Angus and Henry were judged are ultimately inadequate. Because Angus was beaten and forced to submit a confession by the Hong Kong police. The jurors puzzle over him, but most seem convinced by his testimony’s anecdotal details. Angus often yells, and his speech is childish, but he has an answer for everything, like why did he try to patch the holes in his bathroom (vermin infestation) or why did he allow some forms of evidence to be used against him (police brutality). Henry insists that he didn’t make Angus do anything he didn’t want to. He might be right.

Ultimately, “The Sparring Partner” burrows deeper into the tics and trends of previous Hong Kong trial thrillers like “Remains of a Woman” and “The Final Judgement,” both of which dramatized the same real-life murder trial. In that case, a married couple was implicated in a drug-fueled homicide, which they then covered up by dismembering, dissolving, and storing their victim’s body in a metal container full of acid. “The Final Judgement” and “Remains of a Woman” are about women who cannot face the truth about their respective partners. “The Sparring Partner” is more about the culpability and partiality of a jury of Hong Kong residents, some of whom have read about this case in the tabloids, despite being told they should not.