Over the Edge by Irene Hannon

Trauma survivor Lindsey Barnes hasn’t fully recovered from the ordeal that almost took her life, and now she’s in the middle of another crisis. Not only is she the sole witness in a high-profile murder case, but it also appears someone is trying to cast doubts on her mental stability.
Police detective Jack Tucker doesn’t know what to make of her story, especially when her elusive enemy leaves no evidence behind to lend credence to her claims. Yet the more he gets to know the appealing personal chef, the more he’s convinced someone is targeting not only her sanity, but her life.
And unless they can figure out who is behind the campaign to undermine her credibility, a murderer could slip away–leaving more than one body in his or her wake.