“Why did you ask,” Larkin questioned. “Specifically about OSHA.”

“Employers are required by law to keep documentation regarding any violations involving toxic substances for thirty years. I figured that’s bound to happen now and then—isopropylamine is a volatile compound found in most insecticides and this is a parks department. And since HR wouldn’t have the personnel files of employees from the ’90s if they’ve moved on, an OSHA report is better than nothing. So-and-so might remember old coworkers, might still be in regular communication, that sort of thing. At least it would be a starting point.”

Larkin pivoted on his heel to stare at Doyle straight on, albeit he did have to tilt his head up.

Doyle must have sensed the stare, because he turned and mimicked Larkin’s stance. “What?”

“That’s very smart.”

“Should I be insulted?”

“I don’t see why you would be. It was a compliment.”

Doyle was smiling again—not that larger-than-life grin that encompassed his entire face, his entire body, the air around him, but one of subtle bemusement. “I am a detective, Larkin.”

“I know that.”

“Okay.”

Larkin studied Doyle a moment longer before saying, “A judge won’t sign a warrant for those records. I have nothing but a gut impression.”

Doyle slid his hands into his trouser pockets. A strangled breeze rustled his artfully mussed hair. “You suspect an employee from the ’90s because they had the means?”

“It’s more than that.”

“Lay it on me.”

Larkin narrowed his eyes slightly before asking in that same neutral tone, “Are you familiar with the case of Larissa Brown.”

“No.”

“Train conductor for the MTA. Mother of two young daughters—four and two years old. On May 4, 2015, after failing to drop her children off at her mother’s, who babysat during the day while Larissa and her husband, Donald, were both at work, and after being unable to reach Larissa by phone, her mother called the police. Donald worked in construction and had left for his jobsite two hours earlier. In their apartment, there were no signs of foul play. No indication she’d packed for an impromptu trip, although the baby’s diaper bag was missing. She and the little girls had, for all intents and purposes, simply vanished.”

“Are they still missing?” Doyle asked.

“No. They’re dead.”

“Back up.”