[3] Born Isser Birenzweig in Radomsko in the Russian Empire (today in Poland), Be'eri was one of a group of young men known as the "Six from Bedzin", who were later the founders of Migdal.

On 30 June 1948, Tobianski was taken into custody and interrogated by Be'eri, David Kron, Binyamin Gibli and Avraham Kidron during a drumhead court-martial.

Be'eri had already prepared a firing squad consisting of six soldiers from the Palmach Yiftach Brigade, which was in control of the Jerusalem corridor zone.

The civilian court found that, as there was a ceasefire in effect at the time, any information supposedly passed by Tobianski could not have served the Jordanian artillery.

Be'eri's three fellow interrogators, Binyamin Gibli, David Kron and Avraham Kidron, who also were Tobianski's judges in the afternoon field court-martial, were not charged and tried in court.

In his memoir, David Kron wrote that despite the official investigation, he was convinced that Tobianski had been guilty and that Be'eri had the full authority to act the way he had.