Elmer Lincoln Irey

Elmer Lincoln Irey (1888 – July 19, 1948) was a United States Treasury Department official and director of the Internal Revenue Service's lead investigative unit during the federal tax evasion prosecution of Chicago mobster Al Capone.

Appointed Chief of the Treasury Department's Internal Revenue Service Enforcement Branch in 1919, Irey would form one of the most successful investigative teams in the history of American law enforcement with agent Frank J. Wilson leading the hundred-man unit of "T-men" in a three-year investigation against Capone's criminal organization the "Chicago Outfit". Despite attempted jury tampering and death threats against Wilson, Irey's investigation succeeded in the conviction of Capone for tax evasion in 1931.

During the Lindbergh kidnapping, some sources indicate that Irey insisted on tracking the serial numbers on the gold certificates used as ransom money (which ultimately led to the arrest and conviction of Bruno Richard Hauptmann). Other sources credit James W. Wilson.