If you're thinking MANNIX when you see this episode, you are correct. Stephen Kandel (who passed in 2023) may have been inspired by an episode called "Cry Silence" from Season 6, a few years earlier. Anthony Zerbe played a priest who "hears" a killer confess to a murder, but can't do anything because of his sacred vows.
Changing actors here, Laurence Luckinbill (married to Lucie Arnaz) plays Father Vecchio, quite in the same predicament. The frustrating part is the church code of silence, reminiscent of Hitchcock's I CONFESS. Where Harry enters the case, and thanks to Stephen Kandel, it's a unique mystery. Unlike in MANNIX, Father Vecchio is able to give Harry one valuable clue, a verse from a Shakespeare poem, mentioning death and a connection to a killer of multiple victims.
Terrific cast. John Doucette plays the bishop, and looking the part. Comedian J. Edward McKinley (Kramer) guest stars, often seen on BEWITCHED. Charles Drake plays Marty, a staple in many classic films (THE SWIMMER), also WAGON TRAIN. Featuring two excellent actresses; Mary Murphy (known for THE WILD ONE) and Carol Rossen (Marian).
Walter McGinn plays Eric Press, his career cut short a few years later when he was killed in an accident.
You definitely have to see Harry piece this whodunit together. Directed by Paul Wendkos, known for I SPY and THE INVADERS.
SEASON 1 EPISODE 4 remastered Warner Brothers dvd box set. 6 dvds. Released 2012. Seasons 1 and 2 box sets, with terrific covers.