(Played by Actress Linda Blair)
Diane Ballard is a character from the "Supernatural" episode "The Usual Suspects," from season 2. She played a policewoman who thought Sam and Dean had killed a woman, but as she found out, the supernatural was involved in the death. I'm using her in an AU context here in that she's still a policewoman, but from the Boston area, and her previous encounter with the Winchesters involved John and Dean instead. Diane has a different partner here as well.
When I named Stacy Ballard and her family, I took the last name from an acquaintance of mine at the time. Later, I decided I wanted to have Diane Ballard in the story as well, and I thought hm, wouldn't it be kind of cool if she could be somehow related to that family? So that's how it happened. (She's the sister of Miranda Ballard's ex-husband, her sister-in-law.)
The fact that she and Lassiter McNeal's wife have the same first name is a coincidence; Diane McNeal was named way back before "Supernatural" even existed.
there really is a tape