Murder In Gotham

Description for MURDER IN GOTHAM by Isidore Haiblum:

At twenty-nine, Morris Weiss has already had three careers---as a Golden Gloves champion, as a sergeant in the army, and now as a private detective. His latest job should be a standard missing person case, but it might just turn out to be his last. The wife of the vanished man doesn't want to go to the police, and Morris can't blame her. What do the cops know about the jostling Lower East Side, where candy stores are fronts for gambling joints, seedy clubs share space with bakeries, and Yiddish is the lingua franca? Morris, however, knows plenty--- and he's about to learn more....

This is #2 in a Weiss/Weiss Mystery series.