I'd also recommend anyone following this subject "Our People - Discovering Lithuania's Hidden Holocaust",  describing a journey of discovery in 1915 through Lithuania by a respected non-Jewish Lithuanian investigative journalist Rūte Vanagaitē who discovered some of her family were involved in the murder of Jews in WW2, teamed up with a Nazi Hunter Efraim Zuroff.  Initially suspicious of each other, they ended up producing a quite remarkable book. Rūte it seems was made unwelcome in her own country after the publication and now lives in Jerusalem. It was one of the highlights of the recent Jewish Book Week. Extremely harrowing but totally compelling. It was published in 2016 but I think only translated to English last year

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Ian Charles
London, UK