How did they know he did it?

Question

A man murders his wife with a knife in their car. Nobody is around to see this. He throws her out of the car being careful not to leave any fingerprints on her body. Next he throws the knife off from a cliff into the sea where it will never be found and he goes home. An hour later the police call him and tell him that his wife has been murdered and he needs to come to the scene of the crime immediately. As soon as he arrives, he is arrested.

How did they know he did it?

Answer 1

He never ask the cop where the scene of the crime was so they knew that he had murdered his wife.

Answer 2

because police not gave the address even he reached at there .

Answer 3

There are two things once is the Car Tyre Prints that were present on crime scene and
When he murdered his wife he cleaned his fingerprints on her wife's body but he didn't cleaned the car, as when he had murdered his wife in Car, his wife's blood drops would have been there in Car.