sentences:  In the aftermath of the attack on Fort Sumter, Lincoln suspended habeas corpus and began to imprison suspected Confederate sympathizers.In 1861, Seward set up a special office in the State Department designed to monitor internal security, and the federal government and local police officers worked together to suppress those suspected of actively supporting the Confederacy.Among those imprisoned was John Merryman, an officer of the Maryland militia who had cut telegraph lines leading to Washington.