One of the witnesses called for the trial is Samuel K., a Trawniki man himself, as Der Spiegel informs us.
He served at Belzec as a guard. Turns out he was never prosecuted, even though he had been interrogated by the German authorities in 1969, 1975 and 1980. Apparently noting this curious double standard, the Ludwigsburg Central Office of the State Justice Administration for the Investigation of National Socialist Crimes has started an official inquiry regarding his past.
There are two more interesting bits in this story that caught my eye. First of all, the man's testimony. He never denied what happened in Belzec:
Uns war allen klar, dass dort die Juden vernichtet und später dann auch verbrannt wurden.
We were all aware that Jews were being exterminated there, and later also burnt.
The second bit is the possible charge against Samuel K.:
dringend verdächtig, Beihilfe zu der grausamen Ermordung von mindestens 434.000 Menschen geleistet zu haben
strongly suspected to have aided the brutal murder of at least 434,000 people
The main German body dealing with the prosecution of Nazi war criminals now seems to accept the Hoefle telegram's number of Jewish victims of Belzec. Not long ago the reasonable estimates ranged from about 500,000 to 600,000, but the telegram found and published [PDF] in 2001 by historians Tyas and Witte put the number at 434,508 victims until the end of 1942 (and Belzec stopped functioning at the end of 1942). Thus the new research enters the "public sphere", slowly but surely.