My Grandparents have an FBI Nazi war crimes file. Although the National Archives and Research Administration (NARA) has a disclaimer (not all in those files are necessarily Nazi war criminals), our family’s name is still in that list, and to add another insult,one that includes monsters such as ADOLF HITLER, HEINRICH HIMMLER, ADOLF EICHMANN, JOSEF MENGELE, ERIC VON DEM BACH (Commander who lead the reprisals against the Warsaw uprising). Since people do not have access to those documents, I, Nicolas de Koenigsberg, created this blog to set the record straight: NOT ONE OF MY FAMILY HAS EVER BEEN A NAZI WAR CRIMINAL.
The Paragraph before last says:
“It will be noted that additional invetigation failed to reflect that the Koenigsbergs were dealing in looted art”.
…this report is being distributed as the original suspicion, that the art treassurs in the posession of the subjects were looted from occupied Europe, is apparently unfounded
As no evidence has been discovered to suspect the origin of the art treassurs possessed by the subjects, this case is being closed.
“No evidence of pro-Nazi sympathies or espionage developed.Art and antique buisness reported to be legitimate. Sons Victor and Nicolas Jr. presently in the US Army”
de Koenigsberg family 
There is a large antique picture of a KOENIGSBERG couple being sold on ebay. Maybe from Clay co. Mo.
I’m doing some researches on the Nicolas Koenigsberg activities as art dealer.
Do you have any record on a picture by Boilly sold by him ?
He had the picture for sale in 1939 according to an old advert.
Were you able to find out any information? I am doing a very similar thing.
I am also trying to research a picture, sold in 1966 by Nicolas de Koenigsberg, but not sure how to find further information. I can totally understand however how one would wish to clarify the truth of any purported allegations of this nature.
Just as an extra piece of information, the picture I’m researching is a self portrait by Angelica Kauffman, not unlike another picture I believe was in the Paula de Koenigsberg collection by Le Brun (not a self portrait). So clearly even 75 years ago, someone in this family rated female painters, fashionable or not.
I am a researcher at the Nelson-Atkins Museum of Art and believe the Koenigsbergs sold out Greuze Head of a Girl. https://art.nelson-atkins.org/objects/19831/
I would love to know if there is documentation for their ownership of this painting.