I agree with this, and I have an idea that might help. Since there are really not many ways to track down someone who committed a mugging, we need more ways to get IC proof. Maybe to help with this and add to the server's roleplay, we might be able to get something added that maybe could be left on scene and taken by only the people in the faction that got mugged/mugger", even by only using maybe a /me to get the evidence, or maybe an IC item. For example, maybe the perpetrator didn't wear gloves when restraining a victim and left fingerprints on them or some type of DNA to be captured. After being restrained, maybe somebody could do something like this, "/me uses a Fingerprint testing Kit on restraints to test for fingerprint. Then have the staff decide the outcome whether they had gloves on or not(a clip might help). Whether the mugger had gloves or didn't. This could even be a way for factions to use corrupt cops to potentially find out whose DNA/Fingerprints it was and if they are in the system through RP. I'm not saying that this is the only way this could be done, but I think it's something to think about and could be an alternative to finding out who mugged someone while adding RP and helping people get revenge on their muggers. Once you have 100% undeniable proof that someone mugged you through this, you could call the staff and have them set PK active.
As for how this could work, maybe up to 15-30 minutes after the mugging occurred, someone could use a Fingerprint testing kit or something of the matter that could be used to collect the evidence. Maybe there could be some type of "Fingerprint Testing Kit" at the barge that someone could buy and use IC to collect information. This item, when used, might do a /me that says "testing for Fingerprints" or something of the nature, and then add a "Fingerprint slide" to your inventory when used. Then, when staff are available, they can rule whether the evidence is credible, and can be used ic, as they do have the logs to show(or clip).
I'm not saying that this is the only way, but just giving an example. The current state of mugging is very straightforward, and not a whole lot can be done to muggers. If there was more IC ways to get evidence, then maybe people could find muggers and stop metagaming from occurring. Instead of metagaming and flooding someones dm's after a mugging, they could go IC and try to see if they could collect information somehow and figure out who the mugger is. Something like this would actually provide more real RP to the server and could help all around, in my opinion.