The District - Season 3 Episode 15 Back in the Saddle
Overview: Debreno is assigned to protect a country singer, scheduled to sing at the Kennedy Center Honors, who's receiving death threats; Elsewhere, in an effort to lead by example, Mannion hits the streets as a uniformed cop to make quality-of-life arrests on charges such as disorderly conduct, gambling and prostitution. But one of his arrests sparks a chain of events that leads to the reopening of a cold-case murder.