Copycat Killer in Bloomington, MN

In my next case, imitation isn't the sincerest form of flattery when it leads to murder...
Mary Ruth Steinman is a magnet for controversy, but she's good for business. At least until my grumpy Persian meets her and tries to bite her. Soon, it's all I can do to keep my business running and my cat happy. But when the author is found dead after a signing, Tattered Pages is thrust into the news once again. And as much as I'd like to blame my cat, Poppy is no murderer. Plus, she doesn't have opposable thumbs.
So ... who in Silverwood Hollow held a grudge big enough for murder this time?