Bierman called in sick to work during the morning of February 22, 1999 in Felton, California. He was employed with the Citizens Utility water company. His truck was discovered abandoned on San Lorenzo Way, near the San Lorenzo River, shortly afterwards. It was parked near a landslide, where Bierman had done emergency pipe repairs several days before he went missing. The keys in the ignition and there were post-it notes all over the dash to remind Bierman of his daily tasks. There was no sign of Bierman at the scene.

Bierman lived alone and was not reported as a missing person for several days. He left a sack of groceries behind at his home, with a receipt indicating he bought them days before he was reported missing. Investigators theorized he had slipped in the mud and fallen into the river at the place where his truck was parked. An extensive search of the surrounding area and the river produced no evidence as to Bierman's whereabouts. He has never been heard from again and his case remains unsolved.