“Don’t give him anything, Dad. No water, no tea, not even a drop of medicine. And please don’t open the blue envelope in the diaper bag.”

That was the last thing Vanessa said to me before getting into the truck with my son Mason and leaving Lucas, my six-month-old grandson, with me that Saturday morning in Savannah.

I was sixty-five years old and had spent nearly three decades working as an auditor in financial fraud investigations. I had learned to distrust signatures that were too perfect, accounts that didn’t add up, and people who answered before hearing the question. But I never imagined I would have to apply that instinct to my own family.

Lucas wasn’t acting like himself. Normally, as soon as I picked him up, he would wrap his entire hand around my thumb. That day, he barely opened his eyes.

“Is he sick?” I asked.

“He slept badly,” Vanessa answered too quickly. “He’ll probably sleep all morning.”

Mason avoided looking at me. He said they were going to the wake of Walter Higgins, an accountant at his transportation company who had supposedly died of a heart attack a few days earlier.

The name made me uneasy. Walter had sent me an email two weeks earlier: “Mr. Miller, I need to speak with you before it’s too late.” I never replied. I thought it could wait.

Mason left the diaper bag in the room where I kept a portable crib. Vanessa went in there and stayed for almost ten minutes. When she came out, she repeated that I wasn’t to open the blue envelope or take Lucas out of the house unless it was absolutely necessary.

Fifteen minutes later, Lucas let out a high-pitched scream.

His body went rigid in my arms. His back arched, he suddenly stopped crying, and his lips began turning blue.

I called 911 with trembling hands.

At the emergency room, the pediatrician took off his onesie to examine him and froze when he saw his right arm. There were three small yellowish bruises and, near the crease of his elbow, a tiny, precise mark.

“Did you do this to him?” he asked.

“Of course not!”

The doctor looked at the nurse.

“Take samples. And notify the Public Prosecutor’s Office and the Child Protection Agency. Now.”

I felt the floor disappear beneath me.

I called Mason four times. When he finally answered, he didn’t even ask whether his son was breathing.

“Dad… did you already tell them what you gave him?”

I froze.

“What did you say?”

“Nothing. I’m just asking if you told them you gave him something to drink.”

“Your son almost stopped breathing, and you want to know what I told the doctors.”

There was a silence.

“We’re on our way.”

He hung up.

Forty minutes later, they arrived. Vanessa came in crying, but before looking for Lucas, she first looked at the chairs, the floor, and the diaper bag.

Then she pulled out her phone in front of Officer Karen Miller.

“I wanted to avoid this,” she said, “but my father-in-law has been giving the baby drops to make him sleep for months.”

I was speechless.

Vanessa showed a video from the camera in my own living room. It showed me carrying Lucas toward the hallway; seconds later, the video skipped, and the baby could be heard crying.

Everyone turned to look at me.

I looked at the screen again.

9:17:12.

Then, 9:17:59.

Forty-seven seconds were missing.

And while Vanessa pretended to wipe away her tears, I realized something terrifying: they weren’t trying to explain what had happened to Lucas.