HELP! I need the name of this book!! discussion

I know there was a group of former WWII French resistance fighters trying to solve a murder. One of their friends was a suspect (I think). I also think it was a young woman that died. This is an older book. The one I read was a blue clothbound copy with yellowed pages. I am pretty sure it was part of a series. It was all set in Nice, France and the surrounding area.

It puts me in mind of To Catch a Thief, but that doesn't have the murder.

Thanks for suggesting that. I don't think that's it but maybe I can use it as "like this book."