Complex sentence: After the adjournment, Mongibeaux announced that the part of the interrogation dealing with the charge of plotting against the security of the state was concluded and that he now proposed to deal with the charge of intelligence (collaboration) with the enemy.
Split into simpler sentences: After the adjournment, Mongibeaux announced that the part of the interrogation dealing with the charge of plotting against the security of the state was concluded. He proposed to deal next with the charge of intelligence (collaboration) with the enemy.