Appears to be a pencil drawing with added watercolor. Any idea who this is a portrait of? Signature is incredibly faint. Have provided 3 examples that maybe someone could work their magic on. Pretty sure the last name is Hauser, though the R is not completely clear. First name Krueger? Photos are under glass. Prefer not to open the well sealed back unless I have to.
Kind of my thought as well. However, can not find a portrait of him as a younger man that matches up well.
I too see a bit of a likeness, but the portrait nose is sharper and longer.....not sure I helped or hindered that faint "marking"....as I'm not positive it's actually a signature....I think I might see some numbers in it....more in the top row than the bottom, towards the end...maybe a 6 then 7 and 55.......maybe you can see it better....my eyes are weary tonight!