Complex sentence: Although not ever seen on the show, Chris must have been watching Omar from somewhere nearby, because the next day when he and Monk meet Marlo at the rim shop, Chris informs Marlo that Omar sat on Monks crib all night.
Split into simpler sentences: Although not ever seen on the show Chris is watching Omar from somewhere nearby. The next day Chris and Monk meet Marlo at the rim shop and Chris informs Marlo that Omar sat on Monks crib all night.