I'm only just now getting this case on my radar. In the back of my mind, I must have been aware of it in 1976, since I lived in the DC area. Strangely, I swear I actually met this guy before then: BB's seeming really familiar, and our personal circumstances could easily have overlapped somewhere. Weird.
Interesting that he's fluent in Serbo-Croatian. He could, actually, have fled to Yugoslavia and blended easily. I went through Yugoslavia on a train a couple of years earlier, and it was a forbidding place, terrifying. I got there via Trieste in Italy. He could so easily have done the exact same route.
His Italian skills evidently also got him the Addis post (and from there to other African posts): Somalia would have been another place to flee with Italian skill. Or else he could have gone somewhere Italian but obscure-ish at that time: Sardinia or even among the mafiosi in Sicily.
With fluent Spanish, he could have easily buried himself in South or Central America, along with all the ex-Nazis and others who managed to secrete themselves there over the years. In those days down there, you'd see occasional blonde and blue-eyed kids show up in your universe, and you could guess their parentage, and no one would be paying attention. (When I was 10 and lived down there, I innocently introduced myself in German to a blonde-haired, blue-eyed kid at school, although she didn't speak any German lol: I'll bet her parents did.) Anyway, with the strange cast of characters and hucksters (many Americans in these categories) in some of those places, it would have been easy to hide out.
I wonder how much money BB had access to? DOS paid very little, and with 3-4 kids, likely little savings.
BB got sidelined early from the DOS (his last post is
), and that would likely say something about an inability to "fit in" or otherwise rubbing people the wrong way.