Then the coroner’s car arrived, slow and deliberate. A man and woman ambled across the grass, and while their gait was not slow, there was no urgency to their movements. Kat, the voices began again. Kat. It’s Kat. Eve Muhly caught Alexa’s eye and made an “I told you so” face. Alexa summoned her with a stern “I’m not kidding this time” wave.

“Who did this?”

Eve shrugged. “I haven’t heard anything about that.”

“Eve.”

“Everyone’s saying Josie Patel must have been there, because she’s so far up Kat’s butt the only time she ever gets out is in the bathroom.” She waited to see if Alexa would appreciate this bit of schoolhouse wit. “But I don’t know for sure.”

“Still, you must have heard something more.” Alexa tried to pack a lot of weight behind those words, letting Eve know that she believed Eve was, if not an eyewitness, then someone who had seen or heard more than she was letting on. “Isn’t there anything else you can tell me, Eve?”

Eve took on an air of injured innocence. “Why, Ms. Cunningham, you’re always saying we shouldn’t talk about things unless we know them firsthand or have talked to someone who has firsthand information.”

Alexa let her go again. An ambulance, a helicopter, a gurney. She thought of three families and the news that awaited them. The parents of the student in the ambulance were the luckiest-the injuries must not be too bad if the police had decided the student could make the trip along north county’s congested roads. The helicopter was potentially bad, proof of life-threatening injuries, but at least those parents could hope for a good outcome. And everywhere else in Glendale, parents would be given the gift of learning that their dread was groundless, that their children were alive and well.

Only one set of parents wouldn’t be let off the hook. Alexa had a mental image of these parents, alone in the middle-school cafeteria, seeing family after family reunited, watching the door nervously to see when their child would be returned to them.

But surely Barbara would get to the parents of the dead child as quickly as possible, would not prolong this agony of wondering. Alexa could only hope that Barbara would manage to express herself warmly and openly, eschewing her usual bureaucrat-speak. Not a school shooting but a shooting at a school. What an utterly strange distinction to make in the midst of a crisis. She might as well have said, Not a bank robbery but a robbery at the bank. It was as if Barbara wanted to establish that Glendale High School could not be to blame for what had happened there, that it was as much a victim of circumstance as whatever students had been claimed by today’s events.

Alexa glanced back at the building. It looked smug to her, as if it knew in what low esteem it was held and was happy for this moment of revenge against those who had reviled it.

When Baltimore County began training its police officers in the new response protocol for school shootings-“The latest trend, if you please,” as Sergeant Harold Lenhardt liked to say-Lenhardt knew he could never follow it to the letter. Not that the policy wasn’t sound, jokes about trends aside. Police departments across the country were all doing the same thing, under various names, abandoning the SWAT model that had proved so disastrous at Columbine. Some places called it homicide-in-progress. In Baltimore County they preferred to define it by the response, First-Four-In. This meant that the first four responding officers, no matter their rank, no matter their normal assignments, went in together, weapons drawn. The idea was to get to the shooter as quickly as possible, limiting the scope of casualties. Step over the dead, step over the wounded, the officers were told. Just stop the kid and contain the damage as soon as you can.

But what if you were the first guy? Lenhardt had wondered. What if you were there alone, outside a school, all by yourself? How could you wait for the others to show up? He didn’t think he would. He was no cowboy, but if the point was to get in as quickly as possible, then what was so magical about the number four? If he got there first, he didn’t think he’d wait for three others. One, maybe, as backup, but even that would be hard.

For now the question of how he would respond would remain moot. Lenhardt and his partner, Kevin Infante, had arrived at Glendale this morning forty minutes after the 911 call came in, summoned only once the first four officers had determined that there was, in fact, a homicide to investigate. The two wounded girls had been carted away, too, adding to Lenhardt’s frustration. There were things to be done, opportunities to be seized, even in seemingly straightforward shootings such as this one, with a suspect already identified. And while even a seasoned homicide cop couldn’t keep a scene pristine when paramedics were running around and victims had to be transported, Lenhardt and Infante might have been a little more vigilant.

“I just wish we had gotten here sooner,” he told Infante, and not for the first time.

“It’s a pendulum like anything else. It’s only a matter of time before a cop gets killed doing it this way, and then they’ll reinvent the wheel, go back to SWAT teams.”

Lenhardt was studying an odd blood trail that seemed to lead to the door. That should make sense-the wounded girls could have bled on the way out, even with paramedics in attendance, and these drops would then be smeared by people running back and forth.

“The theory is they lack focus, these young shooters. Attention deficit disorder, you know? They get a gun, they come to school, they spray some bullets around, and then their attention wanders. I bet if you checked, you’d find the typical high-school shooter doesn’t do well on the verbal section of the SAT.”

“What?” Infante was staring so hard at a stain in the corner that nothing could pierce his concentration. As Infante’s sergeant, Lenhardt had always admired the younger man’s single-minded approach to the job. As his temporary partner, however, Lenhardt was finding Infante’s one-track mind a bit of a drag. It killed a joke, having to repeat it.

“Never mind.”

Of the two girls taken alive from this bathroom, only one of them, a girl with a bullet lodged in her right foot, would be of any immediate help to the detectives. The other survivor, believed to be the shooter, had lost a part of her face, as Lenhardt heard it, and although Shock Trauma might save her life, it was less clear what else could be salvaged-her jaw, her teeth, her brain. Much of the blood around them was undoubtedly hers. She had leaked a lot in the twenty minutes or so before she was transported.

The dead girl, who was still here with them, had died swiftly, from an almost freakishly precise gunshot wound to the chest, maybe straight to the heart, so there was very little of her blood. Was this marksmanship the result of luck or skill? It didn’t jibe with Lenhardt’s knowledge of Glendale -upper middle class, liberal. But then there were still pockets of farms in the area, rural families with old-fashioned values. A girl raised in such circumstances might be comfortable with a gun. If she knew how to use a gun, however, and had always planned to use it on herself, why had she fired into her cheekbone instead of her temple? And why shoot the other girl at all?

One thing he was willing to bet on: The dead girl, the one on the floor, wasn’t the kind who knew anything about guns. She was a girly-girl, all in pink-pink sandals with cloth roses where the thong nestled between the big and second toes, pale pink pants, and a pale pink polo.

Lenhardt had the digital camera, one outfitted with software that made their photos impossible to alter. Infante was using the backup 35-millimeter because you wouldn’t want to hang a murder investigation on something as temperamental as a computer. Clumsily-he still wasn’t comfortable with the little Canon-he paged through the photos he had taken, looking at the blood, the scene, trying to find the story there. Something was off, but he couldn’t say what exactly. He walked over to the windows, the better to see his photos in the diffused light they allowed in, then looked back at the floor. It was such a gray room-gray tile floors, gray stalls, gray walls, a long gray shelf above three white sinks. The only color in the room, aside from the blood and the dead girl, was an uncapped lipstick standing on the ledge, pink and moist. Lenhardt gestured toward it, and Infante bagged it.