[I don't pay before hearing anything. You say it's worthwhile, but I don't even know if the information is worth the money you're asking for. Tell me what you found first, and if it's useful, then you'll get the wire.]
Mark's tone was hard and a little threatening, and A bit her bottom lip in frustration as she heard this. A had seen a lot of deals where one party would double-cross another after getting the information, and sometimes they might even try to kill the second party just so that they don't have to pay them. If she told Mark about what she found now, then she might get double-crossed as well, and there would be nothing she could do about it.