Complex sentence: Peering in the keyhole he saw someone "bending over something on the floor", later he secured a key from the landlord and saw a large packing crate was missing and the floor had been scrubbed.
Split into simpler sentences: Peering in the keyhole, he saw someone "bending over something on the floor". Wheeler later secured a key from the landlord and saw that a large packing crate was missing and that the floor had been scrubbed.