A letter from Abraham Lincoln, after decades of being locked up inside a private collector’s desk, has resurfaced. According to WHYY, a letter signed by the late president “in the final hours of his life” is now being offered for $45,000 by Raab Collection. The Ardmore-based company which researches, buys, and sells documents of historical figures, purchased the letter from an anonymous owner. Collection president Nathan Raab told The Inquirer that he received a call from a woman who found the document after going through her late husband’s writing desk. There was initially “great interest tem…