I have seen several "explanations" for the inaction of Boris III in 
the case of the Jews from the occupied territories.

Some say, while Bulgarian authorities in Aegean Thrace and Macedonia,
Vardar Macedonia, and Eastern Serbia were tolerated by the Nazis, the
jurisdiction was never (formally) transferred. Hence, the King, the
Bulgarian parliament and government didn't have a big say, the
jurisdiction on those territories belonged to the Nazis (those Jews were
not Bulgarian citizens). 

Others claim that because of the lack of mass protests from the local
population (as was the case later in Bulgaria proper) the King could not
justify a refusal to deport those Jews. Yet a third opinion says that
Boris III could have objected but decided he would not be successful
before the Nazis, so he decided to pass on it and make the point against
the deportation of the much larger number of Jews from Bulgaria proper.

So far, all of those theories seem to be pure speculations (since for some 
reason royal archives are still not available to the historians).  

Similarly, it remains a speculation that Boris III was killed by Hitler
in late 1943 for refusing to deport Jews from Bulgaria proper and for
refusing to send even a small number of "volunteers" to the front.  I
have seen such an opinion expressed in a newspaper interview this year
by the author of the article about Bulgaria in the Encyclopedia of the
Holocaust Dr. Avraham Ben-Yakov (you probably know him, who received his
degrees in history at the University of Jerusalem). The fact which is
known to us for sure is that Boris died under mysterious circumstances
shortly after returning from a trip to Berlin. 

By the way, in the same newspaper article Dr. Ben-Yakov mentions a book
about the Bulgarian Jews by Frederick Chary (I am not sure about the
spelling, the article is in Bulgarian).  Could it be that this is you ?
If so, it seems you are one of the most proficient persons (if not the
most proficient person) on the subject in North America (so please
excuse my humble speculations :-)). Provided this is the case, I wonder,
if you would like to contribute any of you papers or excerpts from your
book to the archive ?  I would like to have the issue revealed as fully 
as possible.


Regards,

Plamen
Plamen.Bliznakov@ASU.edu