https://www.bbc.co.uk/news/world-europe-60024228
Arnold van den Bergh, a Jewish man in Amsterdam has been identified as betraying the Franks.
He was a member of the Amsterdam Jewish Council, which was forced to implement Nazi policy in Jewish areas, until it disbanded in 1943 and members were sent to concentration camps.
However Arnold was not sent to a camp, with suggestions that a former member of this group had been ‘feeding the Nazis with information’ in order to keep him and his wife safe.
Evidence has also been found that Otto Frank, Anne’s dad, KNEW about Arnold, however didn’t say anything ‘as not to re-light anti Semitism’
Otto died in August 1980

Pictured: accused betrayer Arnold van den Berg