From Season 7 episode 4 "How to Dial a Murder" A behavioural psychologist whose wife died under suspicious circumstances trains his dogs to kill on command using a telephone.
From S1E6 "Short Fuse" Sneaky heir to a successful chemicals company finds a clever scheme to kill his uncle and CEO of the company. Upon inspecting the scene of a death on a mountain Columbo seems to have some troubles getting up the hill.
