Uncle Rico was in original movie Helter Skelter
The original Helter Skelter (1976) full length movie is available to watch on Youtube if you have any desire. Everyone in it is fantastic, especially the young groundskeeper.
Jon Gries is the actor that played William Garretson in the movie and was pretty good too. He is probably most remembered for his role as Uncle Rico in the Napoleon Dynamite (2004).
If you have not watched either movie lately, both deserve a second viewing.