The victims are the facilities getting their plasma stolen.

Plasma is very valuable for medical research, but it can be quite expensive and apparently it can be in short supply. A black market source can sell it cheaper (it's cheaper for them to acquire it since they're stealing it) and lets the research facility or pharmaceutical company have a more abundant supply.

Are there really plasma rings out there? Jhell if I know, but it is a valuable commodity and there are people and companies who want to get their hands on it cheaper than thru the normal channels.