Understand that this is not a matter of the local Guardia, no matter what country it's happening in, no matter what level of government you're talking about; Knight Errant is a wholly-owned and -operated subsidiary of Ares - a AAA corporation, just like Evo. An Evo citizen (Jack) has just murdered an Ares employee (KE officer - also possibly an Ares citizen) in front of a dozen witnesses (most of them also KE officers, therefore also Ares employees, and thus possibly also Ares citizens), and was subsequently captured by the aforementioned Ares employees. That means he's going to be sitting in a KE/Ares holding cell until KE/Ares decides what to do with him.
Bribing the friggin' DPP ain't gonna do jack shit; it ain't Australia's jurisdiction. This is a Corporate Court matter, or at least a matter governed by the rules and regulations laid down BY the Corporate Court. This is the destruction of corporate property (Citizen/Employee, One (1), Knight Errant subsidiary of Ares Macrotechnology) pure and simple, and Evo is going to have to pay for it. How they choose to pay is up to you - either the 11/5 contact pays through the nose, or goes to Evo and puts his life and career on the line and Evo pays the tab, or (IMO most likely) Mr. 11/5 goes to Evo and they decline to pay the tab, he CAN'T pay the tab, and so Ares does whatever they want to him (up to and including implanting a cortex bomb), while Evo rescinds his SIN on the one hand and Ares tags him with a Criminal SIN on the other, along with other nasty 'you fucked up' shit.
That, personally, is where I'd go - let Jack continue to be played, but let him know that his corporate masters are gone, he's lost major pull with the exec (11/5 goes to, perhaps, 11/3 - because going to the wall for him, even unsuccessfully, is going to have a Negative Impact On Your Contact's Corporate Relationships), and if he torques KE/Ares off, you-as-GM will simply tell him he's gone kablooie.