The District - Season 3 Episode 12 Untouchable

One of Vanessa Cavanaugh's students commits what she taught to be a perfect murder. No evidence, no witnesses. After the murder confesses to Temple and Debreno his crime, he starts to play with Mannion, who can't seem to charge him since the confession wasn't recorded. Mannion is out to get him for the murder of the father of 3 children and ends up finding a way to link the suspect to the murder scene. Meanwhile, Parras works on a Jane Doe case and finds the victim's estranged mother; and Kendall finds it difficult to end her relationship with a married man.