Of course my blood ran cold.
And I can't imagine how much it terrifies writers.
But after the gasping and the wailing and the rending of garments, the next question is "how the hell would you know she was forging offers?"
The way we heard the story, she told clients she had gotten offers that were "bad" and had turned them down on the author's behalf.
That's a HUGE RED FLAG. Reputable agents don't turn down (or accept!) offers without consulting the writer first. Sure, offers get turned down. When they are, the author and I made that choice together.
But if she's forging the offer, how would you know?
This is so rare, you'll probably never need to know BUT:
If you're suspicious ask to see the original email. If it doesn't have the headers of the publishing company, you know you've got problems.
This agent had sold stuff.
We all knew her, many of us liked her.
It's clear she's slipped off the rails in a very terrible way, destroyed her own career and damaged the writers she was supposed to be helping.
Actually there is a silver lining of sorts: a lot of agents have raised their hand to be resources for the writers affected by this situation. It's nice to see that kind of instant, here-let-me-help response.