"Take a look."
Coates lowered his head to the eyepiece. "I see mostly green. A lot of leaves."
"When the wind moves the leaves, you'll see the steps right where De Sallo stood."
"He was firing between moving leaves?" the detective asked. "You're right. I can see the steps."
Gray resumed his position behind the spotting scope. He loosened the clamping screw and rotated the telescope a fraction of an inch. After a moment he said, "Take another look. Don't jostle the scope."
The detective again replaced Gray behind the telescope. "I don't see anything interesting. A fire escape." Coates raised his head to peer out the window. He scratched his cheek. "The fire escape is on the Atonio Building three blocks toward Foley Square. What am I looking for?"
"Another piece of red cloth."
He went back to the eyepiece. "Yeah, I see it."
"De Sallo's killer tied the cloth strip to the fire escape to judge windage, same as he did on that flagpole. There are probably a few more telltales along the twelve hundred fifty yards of Duane Street between here and the courthouse. And he also had the Foley Square trees as a telltale. Let me see the printout we looked at earlier."
Coates lifted from his suit pocket a folded fax from the National Weather Service and passed it to Gray.
As he looked down a column of dot-matrix numbers, Gray said, "At noon that day the wind was blowing a fairly steady twelve miles an hour out of the south."
"And the telltales told him that," the detective concluded.
"Them and this scope. Take another look."
Coates bent over the scope.
Gray said, "By focusing the scope on the target and rotating the eyepiece a quarter to a half turn counterclockwise, a mirage will appear short of the target."
"What kind of a mirage?" Coates asked.
"It's the shimmer, the ascending waves you see over a hot road in the summer. Wind bends those waves in the direction of the air flow. On a clear day, like it was when De Sallo was killed, the mirage would have been pronounced."
Coates fiddled with the eyepiece.
Gray went on: "If the mirage is flowing from the right, which it would have been that day, the wind is coming from either one, two, three, four, or five o'clock. The rifleman would have turned the scope slowly to the right. As the scope turns the mirage will boil. When it does, the direction in which the scope is pointing is the direction from which the wind is blowing."
"So the wind was coming from the rifleman's three o'clock, out of the south," Coates said. "And then how does he estimate how fast it's blowing?"
"The flatter the mirage waves, the faster the wind. That day there would've been some undulation to the mirage, but not much, not with a twelve-mile-an-hour wind."
Gray looked again at the NWS printout. "The humidity that day was close to one hundred percent. The rifleman would have also known that from the mirage waves. The thicker the waves, the more humid it is."
"Why was the killer worried about humidity?" Coates asked.
"As humidity increases, air density increases, which slows the bullet and lowers its point of impact. The marksman would have had to raise the rifle to compensate for the sticky weather."
"So the rifleman would have made adjustments to his scope to account for the wind and humidity?"
"There were undoubtedly elevation and windage turrets in the scope assembly. He would have presighted on the spot directly behind the microphones, but he wouldn't have had time to tune them when the target appeared. So he would have compensated for the breeze and humidity by aligning the barrel to his right."
"How much off-target did he sight?" Coates asked.
"In a twelve-mile-an-hour wind over twelve hundred fifty feet, about thirteen feet."
Coates's chin came up. "Thirteen feet? I was standing about that distance to De Sallo's left when he was killed. And I was up six or eight courthouse steps from him."
"That's right." Gray smiled thinly. "The killer probably had your head in his sights when he pulled the trigger."
The detective was aghast. "What if the wind had suddenly calmed?"
"Then you'd have been… " Gray paused. "What's the word I'm looking for?"
"Tattooed."
"That's it," Gray said.
Coates blurted, "Maybe the killer was after me. I mean, maybe he knew nothing about wind and humidity. He just got my face in his crosshairs and pulled the trigger, hoping I'd go down."
"He had no interest in you," Gray calmed him. "Just De Sallo. From everything we've seen — the setup of his firing position, the telltales, the shot — the guy was an artist."
Coates laughed sharply. "Is that how you snipers think of yourselves? Artists?"
"I don't think about it at all anymore," Gray said.
"You shipped ninety-six guys to the big pachinko game in the sky and you don't think about it?" Coates cackled. "I can die happy now because I've heard everything."
Coates padded around the room. After a moment he said with glee, "Well, lookee here." He pointed to the edge of the mattress covering the main window. A spent cartridge was balanced there.
Gray bent for a closer look. "That's not the fatal bullet's cartridge."
"We'll run a neutron activation analysis on it," Coates said.
"You can tell by looking at it," Gray replied.
"And we'll do an atomic absorption spectrophotometry on it. And we'll do a scanning electron microscopy/energy dispersive X-ray analysis on it."
"Maybe you'll find the red paint on it by then." With a finger, Gray indicated a narrow ring of red just above the cartridge's extractor recess.
Coates peered closely at the shell. "Looks like fingernail polish to me. What's it doing on a shell?"
"It's the rifleman's sign. He carries an empty red shell and leaves it behind as a signature."
"Like your paper star? Any chance you know the rifleman? A sniper who leaves a painted cartridge?"
"Never heard of him," Gray answered. "But I've been out of the business awhile." Gray looked at his watch. "I'm going back to my kids. Maybe we'll get to the zoo yet today."
Gray followed the police detective toward the door. Two crime-scene investigators entered the apartment. One wore a salt-and-pepper goatee and had a jeweler's loupe attached to his spectacles. He carried two carpenter's toolboxes. The second CSI detective had a bunched face and a leprous complexion. A camcorder hung from his shoulder.
The bearded detective asked as he passed, "Smell anything, Coates?"
"Not until just now." Coates pointed to the empty cartridge, and the investigator opened a box to pull a plastic sack from a roll.
Detective Coates started down the hall. Gray followed. The superintendent had disappeared.
Coates said, "Christ, a paper star and a red shell. Cases for an insane asylum somewhere. And from what I read in your service file, you came close."
"Not that close," Gray said.
"You got pretty damn close to the loony bin," Coates insisted.
"Not that close." Gray felt like he was arguing with his son, John. "Give me a piece of paper from your notebook, will you, Pete?"
The detective lifted a small spiral binder from his coat pocket, tore out a page, and passed it to Gray.
Coates said, "Speaking professionally as a policeman, I can understand how giving the doughnut to ninety-six guys could put you on Valium by the truckload."
Gray's hands worked rapidly. The slip of paper seemed to leap into life.
When they reached the elevator, Gray handed the paper back to Coates. "A little souvenir."
An instant passed before the detective recognized the white star in his palm. He recoiled and his hand flew to his side. The star fluttered to the floor.
The elevator opened.
"That scared the crap out of me, Owen," he said huskily.