Princeton’s Mudd Manuscript Library is now home to a collection of documents from a 1944 tax-fraud investigation linked to Lyndon B. Johnson, then a young ­congressman.

The records of IRS investigator Elmer Charles Werner provide details from his investigation of Brown & Root, a Texas building firm that may have funneled money covertly into Johnson’s failed U.S. Senate campaign in 1941. The White House intervened before Johnson could be questioned, and Brown & Root paid a fine for its actions.

Biographer Robert A. Caro ’57 relied on the Werner documents to examine the case in The Years of Lyndon Johnson: The Path to Power, the first book in his four-volume series on LBJ’s life and career.

Julia Werner Gary, Werner’s daughter, told The Star-Ledger that she chose to donate her late father’s records to Princeton for two reasons: Caro has said that he plans to send his papers to Mudd; and Johnson’s presidential library would not guarantee that all materials would be made available to researchers.