Rising Damp S1E5 (The Prowler)

Whilst calling the cat in, Rigsby hears Ruth scream. She has seen a prowler staring at her through the window. A policeman called Baker is soon on the scene and interviews the household, telling Rigsby to check that the money he keeps hidden under the floor-boards is still there, which Rigsby does, in Baker's presence. Only after Baker has gone and the real police arrive, does Rigsby discover that Baker was an impostor, who has stolen his money.