Complex sentence: Most were returned to Yugoslavia by the British military administration, of whom many were executed by the new communist authorities; the total number of Domobranci summarily executed in mass executions by the authorities exceeds 12,000.
Split into simpler sentences: Most were returned to Yugoslavia by the British military administration, of whom many were executed by the new communist authorities. The total number of Domobranci summarily executed in mass executions by the authorities exceeds 12,000.