After a series of reverses at the front, the Bolsheviks' War Commissar, Trotsky, instituted increasingly harsh measures in order to prevent unauthorised withdrawals, desertions and mutinies in the Red Army. In the field the Cheka special investigations forces, termed the "Special Punitive Department of the All-Russian Extraordinary Commission for Combat of Counter-Revolution and Sabotage" or "Special Punitive Brigades", followed the Red Army, conducting field tribunals and summary executions of soldiers and officers who deserted, retreated from their positions or failed to display sufficient offensive zeal.The Cheka special investigations forces were also charged with the detection of sabotage and counter-revolutionary activity by Red Army soldiers and commanders. Trotsky extended the use of the death penalty to the occasional political commissar whose detachment retreated or broke in the face of the enemy. In August, frustrated at continued reports of Red Army troops breaking under fire, Trotsky authorised the formation of barrier troops – stationed behind unreliable Red Army units and given orders to shoot anyone withdrawing from the battle line without authorisation.