https://www.cnet.com/news/the-clovehitch-killer-review-suburban-america-at-its-darkest-best/

In the browns and beiges of suburbia, quiet teenager Tyler (Charlie Plummer of Boardwalk Empire) spends his nights sneaking out to meet girls in his dad's car. But one night mid-hookup he discovers a cutout from a porn magazine -- that doesn't belong to him. Night ruined, his suspicions turn to his dad Don (the brilliantly creepy Dylan McDermott), despite this squeaky-clean reputation as a boy scout leader and religious man.

Don dutifully instructs scouts on how to hold a flag for a memorial commemorating victims of the Clovehitch Killer, a still-at-large serial killer who bound and tortured women and left a "clove hitch" knot behind as a calling card.