there is a killer born without any skin killing humans and ripping their skin off and wearing it like it was born with it, and it helps it blend in, so the killer could be anyone, the killer could even had killed your loved one and wear its skin and pretend its your relative without you knowing, the only ways to spot it is its eyes, if someone you know has blue eyes but then their eye color switches to Amber, know that its the killer, also its voice can help identifying it too