Cisco and Caitlin stared at the empty space where Barry had been standing.
Wells looked at the same empty space.
"The gas sample," he said, after a moment. "How exactly did he—"
"He ran into the meta on the street," Caitlin said. "A female judge. Barry pulled her out of the elevator." She was already moving toward the computer. "I'm pulling the mall's elevator footage to confirm the ID."
"And I've got the sample." Cisco held up the bottle as he moved toward the analysis bench. "Give me twenty minutes and we'll have a compound breakdown for Caitlin to work from."
Wells watched them both move into position with the synchronized efficiency of a team that had been doing this for a while. He sat with the strange quality of the morning for a moment.
"One morning," he said. "You have a gas sample, a probable ID on the killer, and a lead on the next target." He looked between them. "The gas mask on Barry's head — was that your idea?"
"The mall's AV system, actually," Caitlin said, not looking up from the monitor. "It's a long story—"
"Guys." Barry's voice in the earpiece. "I just thought of something."
"Go ahead." Wells rolled toward the comm panel.
"Even if we figure out how to stop him — we have nowhere to put him. Iron Heights won't hold someone who can turn into gas. He'd be out before the paperwork was filed."
Wells frowned.
"He's still behind you?"
"I deliberately slowed down. He's following. But if he loses interest, I can't exactly herd him." A pause. "And there's no containment option that works — sealed space suffocates him, open space lets him walk out whenever he feels like it."
"That is a genuine problem."
"Wells." Caitlin's voice had changed. "I've got a hit. Facial recognition from the elevator footage matched against law enforcement files — not the prison database, because—" She stopped. "He was executed. The night the particle accelerator exploded. Kyle Nimbus. Already dead on paper, which is why he's not in the active inmate records."
Before anyone could respond to that, Cisco came back out of the analysis lab at a pace that suggested he wanted to be somewhere else. He was holding the bottle at arm's length, slightly greenish around the edges.
"So. Two things." He set the bottle on the far end of the table and stepped back from it. "First: hydrogen cyanide compound with a sedative agent. That's the gas. Second—" He swallowed. "While I was running the molecular analysis, the contents of the bottle... solidified."
He gestured at the bottle. The others looked.
The green mist was gone. In its place was a small, dark piece of organic matter.
"That's part of him," Cisco said. "The gas reverted to tissue when isolated. I don't know if it's muscle or something worse and I have decided not to find out."
Caitlin stared at it with the focused detachment of someone who had attended too many labs to be visibly horrified but was privately reconsidering her career.
Wells said nothing, his expression calibrated to neutral.
"Barry." Cisco turned toward the comm, glad to be looking at something else. "The chemicals in that bottle are consistent with gas chamber execution compounds. You took a physical sample of this man's body without realizing it."
"That's—" Barry's voice had something in it. "That's the chemical cocktail used in lethal injection. And the execution was the night of the accelerator explosion." He was quiet for a second. "So the explosion activated his ability while he was dying."
"He's a Darbinyan family assassin," Caitlin said, still scrolling through the file. "I found him in the organized crime database. The family turned on him — they testified against him in court, got him convicted. He was a pawn they burned."
"Which explains the restaurant," Cisco said. "He went after his own former employers first."
"And the judge was next on the list." Barry's voice shifted. "Wait. I've lost him. He stopped following me. I don't see him anywhere on this street."
"Teresa Howard," Caitlin read from the file. "She delivered the verdict. Sentenced him to death."
"She went home — send me the address—"
"Sending."
A thirty-second gap. Then: "She's not here. House looks clear. Judge Howard seems safe for now."
"Then who's next?" Cisco said.
The answer hit Wells first. He watched the three of them work through it toward the same conclusion, then tapped once on the arm of his wheelchair.
"Barry." His voice was even. "Get to Joe. Right now. Full speed."
A beat.
"It was Joe who led the arrest."
The line was silent for three seconds.
Then Barry's end went quiet in a different way — the particular silence of someone who has already started running.
He hit the precinct floor, changed back to civilian clothes mid-stride, and went through every room in under a minute. Joe's desk. The break room. The briefing room. The evidence lab.
Empty.
He pulled out his phone.