For instance, in Blueprint For Murder he digs up a huge pile. Also, there was another episode where he dug up the entire yard of a playboy because Columbo believed a corpse of his wife was in there (I can't remember the name of this episode though).
That second episode with the yard was "Columbo Cries Wolf". I think it's one of the few episodes with a truly unsympathetic sleazeball villain. Also, Deidre Hall was 100% hotter than any of the magazine models. I'd have bought any issue of "Bachelor World" with her in it.
Better title "Body of Evidence". It fits the Columbo mold by having the villain caught with something to do with his occupation, a female body, which, let's face it was what he sold. It defies the Columbo mold by having the murder actually occur at the end of the episode. I think Ian Buchanon was a wonder as the porno king. He loved Columbo as he fell for all the false clues he and his partner planted. Right up to the last when Columbo pointed out the pager/bracelet missing from the security camera still. Then he just was not happy at all. Another actor I had never heard of, like James Read or Patrick Bauchau, delivering a fine performance.