Scott Drayco watched the video of the murder for the forty-seventh time. All ten seconds of it. One moment, Allison Browning was taking a selfie in front of the District of Columbia War Memorial and then suddenly she and the cellphone fell, leaving only a blur of unfocused motion. If she hadn’t fallen on top of the phone, he wouldn’t even have that much to go on—her attacker didn’t have a chance to grab it before the rest of Allison’s college group headed in that direction.

The knife punctured Allison’s heart and left lung, and she didn’t live long enough to give any details about the assailant. This blurry cellphone recording, preserving the last terror-filled moments of a young life, was all he had. Drayco sighed and played the video again, frame by frame, focusing on the only interesting part from the blur, a flash of red.

The police detectives who’d worked the case the past six months hadn’t determined the source of the red flash. Their official consensus was simply blood and that the killer was an opportunistic thief. But Drayco wasn’t convinced. Neither was the wealthy bank lobbyist who decided he needed a crime consultant and hired Drayco to look into the murder of the granddaughter he’d tearfully called Sissy.

Drayco knew a lot about Allison/Sissy by now. A girl who loved strawberry milkshakes, country music, and collected stuffed penguin toys. A girl whose boyfriend broke up with her a year ago and who hadn’t dated afterward. A girl who wanted to be a doctor growing up but was a senior majoring in environmental science at the time of her death. A girl who opted not to join a sorority but hooked up with a group who called themselves “The Changelings.”

Thanks to Drayco’s friend Detective Zeke Skiles of the MPD, he’d gotten a copy of their report on The Changelings plus a peek at the video interviews. Twelve members in all, straight-A students from privileged families and no rap sheets.

The members were polite and cooperative with the police who effectively struck them from the suspect list. But if there was one thing his former years in the FBI had taught him, it was to pay attention to the “stutters,” the seemingly innocuous little blips.

Caitlynn Carr served as the object of one such stutter. When the cops asked her about The Changelings, she’d hesitated and blinked her eyes several times before responding with the same slick spiel as the others about how the group was all about protecting the environment. Their record seemed to bear out that statement, with fundraising, cleaning up rivers, and lobbying the college to switch to electric vehicles.

But Drayco couldn’t seem to let go of Caitlynn’s “stutter.” So, here he was, in the middle of a rare D.C. snow in December, checking his watch at six o’clock outside the Bauhaus Bar during happy hour. Caitlynn was a regular, and he didn’t have long to wait until she half-stumbled out of the bar with two female friends. All three wore red Santa hats, and one even had a string of blinking Christmas lights draped like a necklace.

He held open the door for the trio and smiled at his target, fortunately not the one with the annoying lights. “You’re Caitlynn Carr, aren’t you?”

She looked up at him and giggled. “Depends on who’s asking.”

The girl wearing the Christmas lights said, “Honey, I don’t care who’s asking as long as he looks like that. If you don’t want to be Caitlynn, I’ll be Caitlynn, and he can unwrap me any time he wants.” She tucked her arm around Drayco’s waist.

Caitlynn giggled again and pushed her aside. “He asked for me, so he’s mine, Lissa. You and Jen go get lost, ’kay?”

Drayco guided Caitlynn toward a different kind of bar a couple of blocks down where he ordered her a quad espresso and himself a black coffee and herded her toward a window seat. The snow had tapered off. Not enough accumulation to be messy but not enough to be pretty, either.

Whenever the door opened, he caught a whiff of rotting food and cigarette butts. He pointed to an overflowing trashcan outside, its contents spilling onto the sidewalk. “What a mess.”

“That’s nothing,” she half-slurred. “You should see the trash downtown. Looks like a goddamn war zone. Broken beer bottles, syringes, used condoms, newspapers that reek of pee. And the people, they’re the worst.”

“The people?”

She leaned toward him and lowered her voice. “Reggie calls them the scum of the earth.”

Drayco took a guess. “You mean the homeless?”