Earlier that day, when Troy had finally connected with the private detective, he’d shared his concerns about Grace; he hadn’t mentioned how the woman had brought him to his knees last night, though, perhaps because it embarrassed him. Still, Sullivan had validated that all of Troy’s worries were reasonable and had suggested that Troy purchase his “express investigative services package,” which was a fancy name for a background check: a report on Grace’s employment history, prior addresses, criminal records, and any other publicly accessible data. Troy realized he could have bought a background check online, but in the likely event that he would need further detective work, he thought it prudent to establish a business relationship with Sullivan. Rod wouldn’t have recommended the guy unless he was worth every penny.

Troy disliked opening pdfs on his phone. He raised the lid of his laptop, powered it on, and accessed the file accompanying the email.

Ten minutes later, he called Sullivan. The investigator answered immediately, an orchestra of revving engines and blaring horns playing in the background, the unmistakable music of a commuter navigating metro Atlanta’s infamous rush-hour traffic.

“Hey, Doc,” Sullivan said. He had a soft Boston accent, so the words came out as hey, dahk. “I’m guessing you read my report, right?”

“This doesn’t help me much at all,” Troy said, glancing at his computer screen. “Grace currently lives in Houston, she’s fifty-nine-years-old and works for a nanny-placement agency? A few prior addresses in Oakland, Philly, and New Orleans, but no criminal record or judgements against her? No record of a marriage or divorce? Big deal. I need more than this to change my wife’s mind about her. There’s got to be some dirt.”

“All right.” Sullivan grunted. “We’ve confirmed her basic story checks out okay. But honestly, Doc, you gotta give me more to work with here.”

Troy ground his teeth. Bruxism was a lifelong, bad habit of his, and worsened when he was under pressure. “What else then?”

“DNA samples, so we can verify maternity.”

Troy was shaking his head. “I told you when we first talked earlier today, they look alike. The resemblance is uncanny. I don’t have any doubt that she’s my wife’s mother.”

“Maybe, but we need to rule it out. Don’t doctors do that, too, when they make a diagnosis? Rule out all the obvious crap first?”

“Differential diagnosis,” Troy said automatically, and recalled a professor’s oft-repeated line from his medical school days. When you hear hoof beats, look for horses, not zebras.

“I have a setup with a local lab that does DNA testing,” Sullivan said. “Comes up all the time in court cases. If you can get me a sample from your wife, and Grace, we can establish beyond all doubt that they’re mother and daughter.”

“Neither of them is going to submit to testing willingly. Especially Grace.”