Per Wikipedia (because the video doesn't actually go into it)

On the morning of November 16, 1957, Plainfield hardware store owner Bernice Worden disappeared. A Plainfield resident reported that the hardware store's truck had been driven out from the rear of the building at around 9:30 a.m. The hardware store saw few customers the entire day; some area residents believed this was because of deer hunting season. Bernice Worden's son, Deputy Sheriff Frank Worden, entered the store around 5:00 p.m. to find the store's cash register open and blood stains on the floor.

Frank Worden told investigators that on the evening before his mother's disappearance, Gein had been in the store, and that he was to have returned the next morning for a gallon of antifreeze. A sales slip for a gallon of antifreeze was the last receipt written by Worden on the morning she disappeared.[20] On the evening of the same day, Gein was arrested at a West Plainfield[a] grocery store, and the Waushara County Sheriff's Department searched the Gein farm.