"Lamb to the Slaughter" - I'm the Detective.

If I was a detective investigating the murder of Patrick Maloney in “Lamb to the Slaughter” by Roald Dahl, I would have  thought of all of the possibilities. Therefore I would have labeled the wife as a prime suspect and analyzed all of the possibilities. I would also ask the wife if they had had any arguments lately. Then after that I would question all the people that have come into contact wih the detective in the past month. Then I would come to a logical conclusion. And that would be that wife killed him