The book I remember was called "Coup d'etat in America". It used a technique that used clear acetate photos of the three tramps taken at about the same angle as in the pictures when the police were leading them for questioning. The theory is that all heads and nose's etc aren't the same. I found the matchup to be perfect for all three of these men. All three were IMHO involved in the WG burglery.
Yeah, that was another book on that, originally published in the 70s and re-released in the early 90s. In the late 80s, after that book was originally published, the tramps were identified from arrest records as Harold Doyle, John Forester Gedney, and Gus W. Abrams. Interviews with Doyle, Gedney, and Abrams' sister confirmed this in the early 90s. There's some info here if you scroll down towards the bottom:
The Three Tramps