The forensics team will probably be able to give a more definite answer, but...judging by appearance, it's not something Lunatic would do. Once he kills his victims, he doesn't stick around, and stealing people's organs doesn't align with his motives.

[A beat.]

As for your last question...I wouldn't be surprised if an imPort did it. Our community is somewhat insulated, and most homicides are committed by someone the victim knows.