“We’ve got a three-way lock on his weapon,” Emerson said.

That got Rodin’s attention.

“He missed with one shot,” Emerson said. “It went into the pool. And you know what? That’s exactly how ballistics labs test-fire a gun. They fire into a long tank of water. The water slows and stops the bullet with absolutely no damage at all. So we’ve got a pristine bullet with all the lands and grooves we need to tie it to an individual rifle.”

“Can you find the individual rifle?”

“We’ve got varnish scrapings from where he steadied it on the wall.”

“That’s good.”

“You bet it is. We find the rifle and we’ll match the varnish and the scratches. It’s as good as DNA.”

“Are you going to find the rifle?”

“We found a shell case. It’s got tool marks on it from the ejector mechanism. So we’ve got a bullet and a case. Together they tie the weapon to the crime. The scratches tie the weapon to the garage location. The garage location ties the crime to the guy who left the trace evidence behind.”

Rodin said nothing. Emerson knew he was thinking about the trial. Technical evidence was sometimes a hard sell. It lacked a human dimension.

“The shell case has got fingerprints on it,” Emerson said. “From when he loaded the magazine. Same thumb and index finger as on the quarter in the parking meter and on the traffic cone. So we can tie the crime to the gun, and the gun to the ammo, and the ammo to the guy who used it. See? It all connects. The guy, the gun, the crime. It’s a total slam dunk.”

“The videotape shows the minivan leaving?”

“Ninety seconds after the first 911 call came in.”

“Who is he?”

“We’ll know just as soon as the fingerprint databases get back to us.”

“If he’s in the databases.”

“I think he was a military shooter,” Emerson said. “All military personnel are in the databases. So it’s just a matter of time.”

It was a matter of forty-nine minutes. A desk guy knocked and entered. He was carrying a sheaf of paper. The paper listed a name, an address, and a history. Plus supplementary information from all over the system. Including a driver’s license photo. Emerson took the paper and glanced through it once. Then again. Then he smiled. Exactly six hours after the first shot was fired, the situation was nailed down tight. A must-win.

“His name is James Barr,” Emerson said.

Silence in the office.

“He’s forty-one years old. He lives twenty minutes from here. He served in the U.S. Army. Honorable discharge fourteen years ago. Infantry specialist, which I’m betting means a sniper. DMV says he drives a six-year-old Dodge Caravan, beige.”

He slid the papers across his desk to Rodin. Rodin picked them up and scanned them through, once, twice, carefully. Emerson watched his eyes. Saw him thinking the guy, the gun, the crime. It was like watching a Vegas slot machine line up three cherries. Bing bing bing! A total certainty.

“James Barr,” Rodin said, like he was savoring the sound of the words. He separated out the DL picture and gazed at it. “James Barr, welcome to a shitload of trouble, sir.”

“Amen to that,” Emerson said, waiting for a compliment.

“I’ll get the warrants,” Rodin said. “Arrest, and searches on his house and car. Judges will be lining up to sign them.”

He left and Emerson called the Chief of Police with the good news. The Chief said he would schedule an eight o’clock press conference for the next morning. He said he wanted Emerson there, front and center. Emerson took that as all the compliment he was going to get, even though he didn’t much like the press.

The warrants were ready within an hour, but the arrest took three hours to set up. First, unmarked surveillance confirmed Barr was home. His place was an unremarkable one-story ranch. Not immaculate, not falling down. Old paint on the siding, fresh blacktop on the driveway. Lights were on and a television set was playing in what was probably the living room. Barr himself was spotted briefly, in a lighted window. He seemed to be alone. Then he seemed to go to bed. Lights went off and the house went quiet. So then there was a pause. It was standard operating procedure to plan carefully for the takedown of an armed man inside a building. The PD SWAT team took charge. They used zoning maps from the city offices and came up with the usual kind of thing. Covert encirclement, overwhelming force on standby front and rear, sudden violent assault on the front and rear doors simultaneously. Emerson was detailed to make the actual arrest, wearing full body armor and a borrowed helmet. An assistant DA would be alongside him, to monitor the legality of the process. Nobody wanted to give a defense attorney anything to chew on later. A paramedic team would be instantly available. Two K9 officers would go along because of the crime-scene investigator’s theory about the dog in the house. Altogether thirty-eight men were involved, and they were all tired. Most of them had been working nineteen hours straight. Their regular watches, plus overtime. So there was a lot of nervous tension in the air. People figured that nobody owned just one automatic weapon. If a guy had one, he had more. Maybe full-auto machine guns. Maybe grenades or bombs.

But the arrest was a walk in the park. James Barr barely even woke up. They broke down his doors at three in the morning and found him asleep, alone in bed. He stayed asleep with fifteen armed men in his bedroom aiming fifteen submachine guns and fifteen flashlight beams at him. He stirred a little when the SWAT commander threw his blankets and pillows to the floor, searching for concealed weapons. He had none. He opened his eyes. Mumbled something that sounded like What? and then went back to sleep, curling up on the flat mattress, hugging himself against the sudden cold. He was a large man, with white skin and black hair that was going gray all over his body. His pajamas were too small for him. He looked slack, and a little older than his forty-one years.

His dog was an old mutt that woke up reluctantly and staggered in from the kitchen. The K9 team captured it immediately and took it straight out to their truck. Emerson took his helmet off and pushed his way through the crowd in the tiny bedroom. Saw a three-quarters-full pint of Jack Daniel’s on the night table, next to an orange prescription bottle that was also three-quarters full. He bent to look at it. Sleeping pills. Legal. Recently prescribed to someone called Rosemary Barr. The label said: Rosemary Barr. Take one for sleeplessness.

“Who’s Rosemary Barr?” the assistant DA asked. “Is he married?”

Emerson glanced around the room. “Doesn’t look like it.”

“Suicide attempt?” the SWAT commander asked.

Emerson shook his head. “He’d have swallowed them all. Plus the whole pint of JD. So I guess Mr. Barr had trouble getting off to sleep tonight, that’s all. After a very busy and productive day.”

The air in the room was stale. It smelled of dirty sheets and an unwashed body.

“We need to be careful here,” the assistant DA said. “He’s impaired right now. His lawyer is going to say he’s not fully capable of understanding Miranda. So we can’t let him say anything. And if he does say something, we can’t listen.”

Emerson called for the paramedics. Told them to check Barr out, to make sure he wasn’t faking, and to make sure he wasn’t about to die on them. They fussed around for a few minutes, listened to his heart, checked his pulse, read the prescription label. Then they pronounced him reasonably fit and healthy, but fast asleep.

“Psychopath,” the SWAT commander said. “No conscience at all.”

“Are we even sure this is the right guy?” the assistant DA asked.

Emerson found a pair of dress pants folded over a chair and checked the pockets. Came out with a small wallet. Found the driver’s license. The name was right, and the address was right. And the photograph was right.