Tesla went to the sink to retrieve a ratty dishtowel, and brought it to the old, newsprint-smudged yellow wall phone. She dialed 911, gave them Brocco’s address and then let the handset fall, the towel unraveling and landing on the worn linoleum.

As she turned to leave, she saw Brocco had five deadbolt locks on the door. His tattered khaki saddlebag, which hung from the knob, was empty.

The ultra-cautious Brocco had let the killer in. The killer stole Brocco’s laptop.

Brocco knew the killer, and the email addresses stored in the laptop weren’t enough.

Tesla hustled down three flights of stairs and stepped into the late-afternoon sun. Shaken, her thoughts occupied by Brocco’s brutal murder as well as by speculation on where Harold might be, she momentarily abandoned the vigilance she applied when she stepped off the Acela in Wilmington, only to taxi to BWI, scurry through the airport as if she were late for a flight, and then pop back on Amtrak to Union Station, buying a ticket using a credit card issued to a woman who worked as an extra at Il Teatro Constanzi in Rome. Now as she hurried to catch the Georgia Avenue bus as it wheezed from its stop, she suddenly remembered, with a startling vividness, an unexpectedly satisfying afternoon she’d spent with Harold at a house on Lake Anna. Were she the type to blush, she would’ve.

Lake Anna, she told herself, unaware that she’d failed to see a man in an old sun-baked Citröen sitting directly across from Brocco’s shabby building. He wore a black stocking cap atop his shaved head; the cap covered a black-and-green tattoo of the jack of spades.

When Tesla leaped onto the bus, the man turned the ignition key, folded the switchblade he’d been using to clean his fingernails, and eased the car out of the spot.

He was waiting when, 33 minutes later, the woman in black pulled out of the Budget lot at Union Station in a dark blue rental, sunglasses on her nose.

There was nothing else they could do. They had no choice.

The Mercedes had kicked up pebbles as Perez parked it at the side of the house. As Middleton hoisted his weary body from the car, Perez said, “Harry, no lights.”

“She’s sleeping?”

“Harry . . . ”

No, of course not. Charley sent her husband to “Scotland” to rescue her father. If she wasn’t pregnant, she’d have been there herself.

Perez pulled the Python.

Groping through darkness, they’d stepped inside the house, and as Perez climbed the stairs to the bedrooms, Middleton put down his briefcase and headed through the kitchen to the living room.

Through the picture window, he saw his daughter’s silhouette on the porch. She was slumped in a wicker chair.

“Charley,” he’d whispered. Then he said her name again, louder this time.

When she didn’t respond, Middleton called to his son-in-law and raced outside.