Empath

She was the empath who would betray empaths if she got the chance. So they'd tried to fix things so that she didn't get the chance.

How did a complete stranger know he was an empath? He rarely if ever talked about it, even to his closest friends. It made people uneasy.

The aura may, in fact, linger around objects or places and that "lingering energy" is what an empath senses and intuits.