"So what do you think it is?" Dean asked his brother as they entered the apartment building. They took the elevator up to the roped off third floor.
"I don't know," Sam said, "I mean it could be anything, there wasn't much remains to go off of."
Dean nodded, "Do you remember that case in Ohio? It was kind of similar to this, but less gruesome."
"Right," Sam recalled. "The witch circle. I'll look for a hex bag in the apartment, EMF too."
The elevator slowed to a stop and their fake FBI badges acting as an all-access pass to the crime scene.
The thin-faced man, older man with a tired face nodded to them - the town's sheriff. "Be careful when you step in, there's blood nearly everywhere in the entrance." It was true. Splattered blood covered the entranceway, it was almost as if Amy Wells had just exploded.
"Why don't you tell me what happened," Dean suggested to the sheriff after the brothers took in the scene, "While my partner here takes a look around." The sheriff nodded in agreement and Sam walked away, exploring the untouched areas of the small apartment.
Despite how hard he tried, he couldn't find a hex bag anywhere. No EMF, either. As Sam could find no other evidence, he made his way to the exit. About a foot from the door, he could hear the EMF monitor spontaneously start it's beeping.
When he and Dean got out of there he said, "It's definitely a spirit. Let's head back to the motel, do some research."
Dean only said, "Call me if you find anything. There's been only one witness, Olivia Marten's boyfriend. I'll go talk to him, see if he saw anything we could use."