Part of the success of the film is due to the excellent acting from Frank Wolff and Raf Vallone. The chemistry between the two is great, especially in the scenes in the morgue and when the father cleans out the dead girls things of the flat. This is a hidden gem if there ever were one.
The poster is one of the favourites in my collection, but unfortunately I haven't been able to find any info on who's responsible for the beautiful artwork.