The Siege (Star Trek Deep Space Nine, No 2)

Deep Space NineTM is forced to curtail entry to the wormhole due to increased graviton emissions, and an air of biting tension settles over the station. This anxiety leads to the murder of an Edeman religious leader, Commander Benjamin Sisko and Security Chief Odo realize they face a larger problem.
Soon Sisko and Odo have more lifeless bodies on their hands and a killer who strikes without motive. Then, both the Edemans and Cardassians arrive threatening to destroy the station unless the murderer is given to them for retribution. In order to save Deep Space Nine and stop the killing, Odo must try to destroy a powerful assassin who is the only link to his mysterious past.