PHILADELPHIA, Dec. 14.
    Col. Wynkoop, late U. S. Marshall, was yesterday killed at Tauraqua, while gunning, by the accidental discharge of a gun in the hands of a servant. He was an officer of the Pennsylvania Regiment in Mexico.

Source:

Unknown, "Death of Colonel Wynkoop," Brooklyn Daily Eagle, Brooklyn, Monday, 14 December 1857, p. 3.