A. B. Cooper

They were planning to go into the Osage Hills when they were joined by J. W. Robinson of the Pinkerton Agency in Bartlesville and A. B. Cooper of the Burns Agency in Kansas City, and, shortly afterwards, by Bartlesville officers John Creed and Harve Parrick.
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Six days after his capture, acting presumably on information supplied by him, A. B. Cooper, officers Creed and Parrick and Julius Payne of Vinita raided Sol Wells' home near Okesa and arrested Earl Holman.

Also joining them was A. B. Cooper, identified by the newspaper as an operative'.Cooper was a private detective, sometimes employed by the Burns Detective Agency, and also a member of the Oklahoma Sheriffs and Peace Officers Association.