Cadfael (1994)

S4E3 The Pilgrim of Hate

Title: The Pilgrim of Hate Plot: An elderly man's corpse is discovered concealed in a sack at the Abbey, prompting Cadfael to suspect foul play. His main suspects are a band of pilgrims, which includes two notorious thieves. To uncover the murderer, Cadfael decides to imprison the entire group, hoping to provoke the killer into revealing themselves.