dunno if i understand what really happened - but...
when you kill a player, this player ( and ALL his chars ) must avoid you. - so ... a killed player should avoid the killer and all his groupmates for 4 hours. he can move back into the system where he was killed in - but only when the killer and all the groupmates are NOT there.
then the killer of the groupmates return there ( they are free to go back there ) - he must again leave. ( this applies to retreat, too. - only that the forbidden system does not "move" with the player that forced a retreat - but is only applied to the system the incident happened ) - the player that either thrusted a long way away so it was a retreat on thrust ... OR the player that FIRST engaged cruise when being fired at MUST leave the system AS SOON AS POSSIBLE - without gabbling about it, without staying in the system, even a long way off.
the player that KILLED someone can at ANY time engage the killed person again and again and again and again. ( that applies to traders being the target, mind )
why does it not apply to fighters / fighting targets? - cause those must stay away from the killer ANYWAY. - if they don t, they violate the rules by involving themselves into the affairs of the killer, hence affecting him. ( that includes being there, talking to others about the killers location etc etc - cause...... see..... they re dead - and dead people don t talk or influence others [ except posting a forum bounty on the killer maybe ] )
self defense. - if the killed player violated the rule by coming back to the killer, - and is shot at - he should at least have the decency to stay out of pvp or anything. - when he is shot at.... there s a clash of rules... sort of.
a player that is shot at can self defend himself - but only when at least 50% of his shields were depleted. - but since he violated the rules anyway by being there, that might or might not apply.
in general, many players don t take the retreat / death rule very serious. - very often i see players engage others and retreat - but NOT leave the system for 4 hours. a player that was killed must avoid the killer for 4 hours. - its not like there s much to interpret about it.