Ok, I've never explained how my prison freekill system works in detail before, so here it is --
Freekilling is considered highly probable if the victim is not marked as having gone in a restricted area, grabbed an item, hurt guards, or murdered guards. The only way this is not freekill is if the prisoner refused to follow orders, i.e. defiance or if it was a legitimate accident, i.e. a crossfire kill.
The system doesn't detect defiance or accidental kills. So, if if the victim is suspected as having been freekilled, the killer gets a chance to /explain their kill. The killer is warned with a popup and chat message in huge red font that they must use the explain command within 40 seconds.
The system makes these checks:
1) If the killer doesn't explain the suspected freekill within that time frame, the game will kill them and revive the victim.
2) If the killer perpetrates another suspected freekill in that same window of time of 40 seconds, console bans them for a few hours.
3) If the killer accrues x amount of suspected freekills, all explained, within y time period, console bans them for 2 weeks for presumably mass freekilling with bogus explanations.
Otherwise, staff can ban users for perceived breaking of the /rules, and there are no set guidelines on those ban lengths.
I hope that clears things up a little.