He moved before the comparison microscope and used the Air Gap method to fix the bullet to the stage with wax so he didn't leave any marks on metal that weren't already there.

"Okay," he talked without looking up, "the rifling is to the left, and we've got six lands and grooves." He began measuring with micrometer jaws. "Land impressions are point oh-seven-four. Groove impressions are point one-five-three. I'm going to enter that into the GRC,- he said, referring to the FBI's computerized General Rifling Characteristics. "Now let's determine the caliber," he spoke abstractedly as he typed.

While the computer raced through its databases, Frost checked the bullet with a vernier measuring device. Not surprisingly, what he found was that the caliber of the Black Talon was.45, and then the GRC came back with a list of twelve brands of firearms that could have fired it. All, except Sig Sauer and several Colts, were military pistols.

"What about the cartridge case?" I said. "Do we know anything about it?"

"I've got it on live video but I haven't run it yet."

He returned to the chair where I had found him when I had first come in and began typing on a workstation connected by modem to an FBI firearms evidence imaging system called DRUGFIRE. The application was part of the massive Crime Analysis Information Network known as CAIN, which Lucy had developed, and the point was to link firearms-related crimes. Succinctly put, I wanted to know if the gun that had killed Danny might have killed or maimed before, especially since the type of ammunition hinted that the assailant was no novice.

The workstation was simple, with its 486 turbo PC connected to a video camera and comparison microscope that made it possible to capture images in real time and in color on a twenty-inch screen. Frost went into another menu and the video display was suddenly filled with a checkerboard of silvery disks representing other.45 cartridge cases, each with unique impressions. The breech face of the Winchester.45 connected to my case was on the top left-hand side, and I could see every mark made by breech block, firing pin, ejector or any of her metal part of the gun that had fired the round into Danny's head.

"Yours has a big drag to the left." Frost showed me what looked like a tail coming out of the circular dent left by the firing pin. "And there's this other mark here, also to the left." He touched the screen with his finger.

"Ejector?" I said.

"Nope, I'd say that's from the firing pin bouncing back."

"Unusual?"

"Well, I'd just say it's unique to this weapon," he replied as he stared. "So we can run this if you want."

Let's.

He pulled up another screen and entered the information he had, such as the hemispherical shape the firing pin had impressed in the soft metal of the printer, and the direction of twist and parallel striation of the microscopic characteristics of the breech face. We did not enter anything about the bullet I had recovered from Danny's brain, for we could not prove that the Black Talon and the cartridge case were related, no matter how much we might suspect it. The examination of those two items of evidence was really unrelated, for lands and grooves and firing pin impressions are as different as fingerprints and footwear. All one can hope is that the stories the witnesses tell are the same.

Amazingly, in this case they were. When Frost executed his search, we had to wait only a minute or two before DRUGFIRE let us know that it had several candidates that might match the small, nickel-plated cylinder found ten feet from Danny's blood.

"Let's see what we've got here." Frost talked to himself as he positioned the top of the list on his screen. "This is your front runner." He dragged his finger across the glass.

"No contest. This one's way ahead of the pack."

"A Sig forty-five P220," I said, looking at him in astonishment. "The cartridge case is matching with a weapon versus another cartridge case?"

"Yes. Damn if it isn't. Jesus Christ."

"Let me make sure I understand this." I could not believe what I was seeing. "You wouldn't have the characteristics of a firearm entered into DRUGFIRE unless that firearm had been turned in to a lab. By the police, for some reason."

"That's how it's done," Frost agreed as he began to print screens. "This Sig forty-five that's in the computer is coming u p as the same one that fired the cartridge found near Danny Webster's body. That much we know right this second. What I've got to do is pull the actual cartridge case from the test fire done when we originally got the gun."

He stood.

I did not move as I continued staring at the list in DRUGFIRE with its symbols and abbreviations that told us about this pistol. It left recoil and drag marks, or its fingerprints, on the cartridge cases of every round it spent. I thought of Ted Eddings' stiff body in the cold waters of the Elizabeth River. I thought of Danny dead near a tunnel that no longer led anywhere.

"Then this gun somehow got back out on the street," I said.

Frost pursed his lips as he opened file drawers. "It would appear that way. But I really don't know the details of why it was entered into the system to begin with." Still rooting around, he added, "I believe the police department that originally turned the weapon in to us was Henrico County.

Let's see, where's CVA5471? We are seriously running out of room in this place."

"This was submitted last fall." I noted the date on the Computer screen. "September twenty-ninth."

"Right. That should be the date the form was completed."

"Do you know why the police turned the gun in?"

"You'd have to call them," Frost said.

"Let's get Marino on it now."

"Good idea."

I called Marino's pager as Frost pulled a file folder. Inside was the usual clear plastic envelope that we used to store the thousands of cartridge cases and shotgun shells that came through Virginia's labs every year.

"Here we go," he said.

"You have any Sig P220s in here?" I got up, too.

"One. It should be on the rack with the other forty-five auto loads."

While He mounted his test-fire cartridge case on the microscope's stage, I walked into a room that was either a nightmare or toy store, depending on Your point of view.

Walls were boards crowded with pistols, revolvers, and Tec- I Is and Tec-9s. It was depressing to think how many deaths were represented by the weapons in this one cramped room, at)(] how many of the cases had been mine.

The Sig Sauer P220 was black, and looked so much like the nine-milfirneter carried by Richmond police that at a glance I could not have told them apart. Of course, on close inspection, the.45 was somewhat bigger, and I suspected its muzzle mark might be different, too.

"Where's the ink pad?" I asked Frost as he leaned over the microscope, lining up both cartridge cases so he could physically compare them side by side.

"In my top desk drawer-," he said as the telephone rang -"Towards the back."

I got out the small tin of fingerprint ink and unfolded a snowy clean cotton twill cloth, which I placed on a thin, soft plastic pad. Frost picked up the phone.

"Hey, Bud. We got a hit on DRUGFIRE," he said, and I knew he was talking to Marino. "Can you run something down?"

He proceeded to tell Marino what he knew. Then Frost said to me as he hung up, "He's going to check with Henrico even as we speak."

"Good," I abstractedly said as I pressed the pistol's barrel into the ink, and then onto the cloth.

"These are definitely distinctive," I said right off as I studied several blackened muzzle marks that clearly showed the combat pistol's front sight blade, recoil guide and shape of the slide.

"You think we could identify that specific type of pistol?" he asked, and he was peering into the microscope again.