My former boss was in a gulag for most of his teens. He was not paid and to this day he has no idea what crime he was convicted of.

Maybe your former boss was bullshitting you. Maybe he knew precisely why he was in prison, but didn’t want to admit his crimes to his employees. It’s pretty common for ex-cons to falsely claim innocence.

He just knows he served time and was targeted by guards because he was Jewish and the Soviets were very bigoted.

There were many prominent Jews in the Bolshevik revolution, and Jews continued to be active members of the Communist Party, in soviets, and in the Politburo.