On multiple occasions, I've observed a "Clean" NPC ship (basically operating as a bounty hunter) opening fire on a "Wanted" NPC ship, then the police ships arrive shortly later and join the attack against the "Wanted" NPC ship. After the "Wanted" NPC ship is destroyed by them, the police leave the "Clean" NPC ship (that started the fight) alone afterwards.
Once I have installed a K Warrant Scanner in my ship, if no other NPC ships are on my radar, then I can open fire on a "Wanted" NPC ship (that hasn't open fired upon me yet) (i.e. that is orange-coloured on my radar) without any repurcussions afterwards. Around the time that I destroy the "Wanted" NPC ship, the police ships usually arrive, scan my ship, and tell me that I have a clean record and that I am free to move along.
However, if I open fire on a "Wanted" NPC ship (that hasn't open fired upon me yet) (i.e. that is orange-coloured on my radar) while any police ships are in the vicinity, then ALL of the police ships and "Clean" NPC ships in the vicinity immediately turn red on my radar, indicating that they may fire upon me at any time in the future. So long as I DON'T fire back at any of the "red" police ships or "red" "Clean" NPC ships, then if I jump away or SuperCruise to a colony, from then on, all police ships (belonging to the faction that controls the system that I opened fire on the "Wanted" NPC ship in) will scan me and tell me that I have a clean record and will leave me alone.