Can anyone recall a movie where there were detectives who had to try to find clues about a murder. The victim had a book in which he kept entries like a bank account for all of the kind deeds he did for others. He also kept track if they repaid his kindness. I think he stopped being kind to people if they never tried to repay his kindness... well eventually one of the people killed him despite all of his old kindnesses. The detectives had to go through all of the transactions in the book and interview the people, in order to figure out who did it...

This movie is probably at least 30 years old but still sticks in my mind! Can anyone help me out with a title?