It's been more than 25 years since workers renovating Abraham Lincoln's home found a letter fragment in a mouse's nest inside a wall.
But researchers think they've finally identified the author of the mystery letter as newspaper editor Andrew Johnston.
Stacy Pratt McDermott is an associate editor of The Papers of Abraham Lincoln.
She compared handwriting on the fragment with other correspondence between Lincoln and Johnston and found it matched.
The (Springfield) State Journal-Register reports that the two men exchanged several letters about poetry and politics.
The March 10, 1846, letter sent from Quincy, Ill., was Johnston's reply to a poem the future president had shared with him.
Papers of Abraham Lincoln Director Daniel Stowell says ``it illuminates an interesting part of Lincoln's career in that he enjoyed poetry.''