Twenty four

 When Dean sees her again, she's wearing a suit that screams FBI. The gun and the badge are his second clue. There's a brief glimpse of surprise in her eyes when she recognizes him, but her gun never wavers.

"Drop the weapon, Agent Mars." He tells her and she almost rolls her eyes.

"Drop yours, Mr. Winchester." Her tone is condescending, they both know enough to see that it's not going to happen.

"I didn't kill those women." This time she does rolls her eyes. People have disappointed her enough that she won't trust easily. "The first murder happened when I was four!"

"You could be a copycat, it could be family business." She's got part of it right. Just the wrong kind of business.

"You know I didn't do it. Call me a private investigator, I was just trying to catch who did."

"You're not a P.I."

 The situation is slipping beyond his control. He can't convince her that he's innocent without opening a whole new can of worms. And Dean won't bring another person to this life.

 Veronica falls to the ground unconscious. Sam stands behind her, she never saw him coming.

 Veronica wakes, twenty minutes later, to paramedics (called in anonymously). Her gun is empty of bullets and her head is supported by a jacket made pillow.

 Dean decides that California and blonde women are nothing but trouble.