There was a gunfight aboard the Mississippi Riverboat, Sunflower while docked at Jacksonville on Feb 9, 1879.
It involved General Lowry of Brandon, a Dr Lowry, John Arnold, and Col D A Holman. Holman killed John Arnold. He was tried and aquited.

I believe John Arnold was my Great-great Grandfather who disappeared on business trip to New Orleans.

Anyone having information on this matter, please contact me. Thanks.