Unmarked grave of John Frederick Parker at Glenwood Cemetery in Washington, D.C., in the United States. Parker was a member of the Metropolitan Police Department in Washington, D.C. He was assigned to guard President Abraham Lincoln at Ford's Theater on April 14, 1865. After Lincoln was seated in his presidential box, Parker remained seated in the dress circle outside the box. He left his post to have a drink in a nearby saloon, and during his absense John Wilkes Booth shot Lincoln. Parker was never charged with dereliction of duty.