[Amethyst Rockstar]

This kill is only valid in overtime.
Basing a kill on a weapon is only suspicious.

This is not metagaming.

Since multiple people can have the same weapon you cannot with 100% certainty know that he did it.
Prior to overtime you need to be 100% sure by either witnessing the complete traitorish act in full, having DNA, or following someone else's KOS direction.

It wasn't based solely on the weapon though. Based on how the map is built, the guy I shot had to either be the killer or have witnessed the firefight and let the killer walk past him which is traitorous.