Answer:
Secretary War Edwin Stanton
Step-by-step explanation:
Secretary War Edwin Stanton was a Lawyer and never served in the Military due to his Asthmatic health condition.
When the President was lay dying, Stanton immediately went to work and started issuing orders to protect other leaders, directing generals' movements and informing the nation of Lincoln's death.
He also began the search for the assassin and his co-conspirators.
He was also responsible for managing the prosecution of those accused.