Thriller film – Need name please. thanks

I remember seeing a film around 1973, that for the life of me I cannot remember the name. It was a US cop thriller movie. The villain was a transvestite. The hero was a plainclothes cop or private eye… not sure which. There was a big fight between the two of them in a public lavatory. The transvestite was shacked up with a woman who dressed as a guy. The hero was not Clint Eastwood… but someone who looked a bit like him. Can anyone help? Many thanks