One was Kowalczyk, the husband of Miss Defina, who had been known to serve as a secretary to Napoleon's illegitimate son Valevsky.
As for another assassin, Daboski, who had been hiding due to grievous bodily harm at the docks, was indeed confirmed to have served in the Polish army, and Talleyrand made direct contact with Daboski's superior through Prince Chartoryski, the leader of the Polish exiles.
Interestingly, according to the Polish lieutenant, after injuring the person, Daboski had contacted many of his old comrades.
It is unknown where this young man heard about the successful case of Fred, the former underground ruler of the East End. Perhaps because of his overwhelming victory over the London hooligans in a dock fight, this brainless Polish soldier thought he could replicate Fred's path to success—establishing his dominion in the East End with a group of ex-military men using nothing but their fists.