Sleuth (1972)

Milo Tindle and Andrew Wyke have something in common, Andrew's wife. In an attempt to find a way out of this without costing Andrew a fortune in alimony, he suggests Milo pretend to rob his house and let him claim the insurance on the stolen jewelry. The problem is that they don't really like each other and each cannot avoid the zinger on the other. The plot has many shifts in which the advantage shifts between Milo and Andrew.