Heck Thomas was one of the most respected deputy marshals that had ever ridden for the Fort Smith Court in the territories. While riding for the court, Heck Thomas had been sent after his share of "hard cases". It's been said of Heck that he had brought to justice more criminals than any other marshal working in the territories. But in October of 1892 he found himself closing in on the most feared gang of outlaws in the southwest, the Dalton Gang.

Heck Thomas found himself in an odd position when chasing the Dalton Boys. He'd worked with Bob and Grat Dalton when they were riding as deputy marshals. He even put in a good word for Grat when Grat was commissioned as a deputy marshal under the Fort Smith Court. He knew their late brother Frank Dalton, and had severed with him on many of hard cases. But when the boys turn bad he was on their trail.

Emmett Dalton would state years later in his autobiography that Heck Thomas was their "nemesis". After each holdup Heck was in the field chasing the gang. However, the boys prove to be difficult quarry to catch. They had an edge, they knew the country, had plenty of friends to hide them out and warn them about the posses, and they knew how the marshals worked. Thus they were able to avoid most of the traps laid for them by the law.

At Red Rock, O.T. the boys would narrowly miss an ambush by an army of deputy marshal, when they decided not to rob the train when it pulled in the station as plan. Something about the train was wrong, the lights in the passenger cars were dim. The boys didn't spring into action as usual, instead they argued among themselves as the train rolled out of sight. Moments later a second train appeared. This time everything seemed normal so the gang struck and robbed it. Lucky for the gang they followed their instincts, because waiting in the dark in those passenger cars of the first train was Heck Thomas and a company of armed deputies just itching to blast the boys out of their boots.

Still Heck stayed on their trail in a persistent chase, never letting the boys stay or rest in any one place to long.

After the Adair robbery in July, the gang had pull its usual trick of splitting up. Heck went after Bob and Emmett figuring that sooner or later the gang would reunite with them for another robbery. He trailed them into the Osage Nation and located their hide-out on Oct. 3. It was to late, 5 members of the gang had already pulled out heading north. He trailed the gang to their campsite on California Creek (about 20 south of Coffeyville, KS) but the gang had left the site the night before (Oct. 4) for a new campsite on Onion Creek near Coffeyville, KS. As he started trailing the gang toward Onion Creek the news came that the boys had been killed in Coffeyville, KS.

Heck would proceed to Coffeyville and identify the bodies for the Wells Fargo Company. Afterwards he was presented a check for $1,500 by the express company in his efforts to bring the gang to justice. But Heck's job was just beginning. With the deaths of the Dalton Boys a new gang was to emerge and apply its talent to the outlaw trade. Heck Thomas would soon find himself tracking down the Wild Bunch, and their leader Bill Dollin "King of the Oklahoma Bandits".