T is for Trespass - Sue Grafton

A miser and a hoarder, Gus Vronsky is so crotchety that after he takes a bad fall, his only living relative is anxious to find him some hired help and get back home as soon as she can.

In an effort to help, Gus's neighbor, private investigator Kinsey Millhone, runs a check on an applicant for the job, Solana Rojas. Social Security, driver's license, nursing certification: It all checks out. And it sounds like she did a good job for her former employers. So Kinsey gives her the thumbs-up, figuring Gus will be the ideal assignment for this diligent, experienced caregiver.

And the real Solana Rojas was indeed an excellent caregiver. But the woman who has stolen her identity is not, and for her, Gus will be the ideal victim...