 Margolis found and published the long-lost diary of Kazimierz Sakowicz, a Polish Christian journalist who witnessed the Ponary massacre outside Vilnius, where tens of thousands of Jews were murdered.Margolis reconstructed Sakowicz's diary from fragments of paper found in lemonade bottles, text written on a 1941 calendar and other papers held in archives that were not accessible under Soviet rule.Beginning in 2008, Lithuanian prosecutor general wanted to question Margolis as part of the investigation of the Koniuchy massacre when Soviet and Jewish partisans killed at least 38 civilians.