In Star Trek we see many times that alien worlds enlist the help of Starfleet/Federation personnel for humanitarian and other purposes, sometimes these are legitimate, however sometimes it turns out that they have another agenda and have in some cases murdered/attempted to murder those said personnel.
One instance of this is displayed in the episode DS9: "Armageddon Game" where Julian Bashir, Miles O'Brien, Dax and Commander Sisko come under attack by the T'Lani and Kellerun, a species that only days earlier wanted their help to destroy deadly weapons named "Harvesters"
It seems strange that in the end of this episode, there are no apparent repercussions suffered by the attempted murderers. Would it not make sense to send Federation ships to arrest them? To my knowledge their ships would be no match and it would be relatively easy to catch them. If not, does this not send a strong message to the rest of the galaxy that you can do whatever you wish to Federation personnel and get away with it?