“Same here—S and S Two. No visual. Heat upstairs, nothing on the ground floor. Heard a click or two a second ago, K.”

“Weapon?”

“Could be. Or maybe just appliances or the furnace, K.”

The ESU officer next to Sachs deployed his officers with hand signals. He, Sachs and two others clustered at the front door, another team of four right behind them. One held the battering ram. The other three covered the windows on the ground and the second floors.

“B Team to One. We’re in position. Got a ladder next to the lit room in the back, K.”

“A Team, in position,” another ESU officer radioed in a whisper.

“We’re no-knock,” Haumann told the teams. “On my count of three, flashbangs into the rooms that have the lights on. Throw ’em hard to get through the shades. On one, simultaneous dynamic entry front and back. B Team, split up, cover the ground floor and basement. A Team, go straight upstairs. Remember, this guy knows how to make IEDs. Look for devices.”

“B Team, copy.”

“A, copy.”

Despite the freezing air Sachs’s palms were sweating inside the tight Nomex gloves. She pulled the right one away and blew into it. Did the same with the left. Then she cinched up the body armor and unsnapped the cover of her spare ammo clip carrier. The other officers had machine guns but Sachs never went for that. She preferred the elegance of a single well-placed round to a spray of lead.

Sachs and the three officers on the primary entry team nodded at one another.

Haumann’s raspy voice began the count. “Six . . . five . . . four . . . three . . .”

The sound of breaking glass filled the crisp air as officers flung the grenades through the windows.

Haumann, continuing calmly: “Two . . . one.”

The sharp crack of the flashbangs shook the windows and bursts of white light filled the house momentarily. The burly officer with the battering ram slammed it into the front door. It crashed open without resistance and in a few seconds the officers were spreading out in the sparsely furnished house.

Flashlight in one hand, gun in the other, Sachs stayed with her team as they worked their way up the stairs.

She began hearing the voices of the other officers calling in as they cleared the basement and the rooms on the ground floor.

One upstairs bedroom was empty, the second, as well.

Then all the rooms were declared clear.

“Where the hell is he?” Sachs muttered.

“Always an adventure, huh?” somebody asked.

“Invisible fucking perp,” came another voice.

Then in her earpiece she heard: “S and S One. Light in the attic just went out. He’s up there.”