It's Always Sunny in Philadelphia (2005)

S10E7 Mac Kills His Dad

Title: Mac Investigates His Father's Innocence Plot: Rumors emerge that Mac's father, Luther, is implicated in a murder case. Determined to prove his dad's innocence, Mac adopts the role of a private investigator. He dives into the case, seeking out clues and interviewing potential witnesses to uncover the truth and exonerate Luther from these serious allegations.