Arkham special detention wing, cell seven.
The door was still locked.
The electronic lock showed green, and all three mechanical bolts were fully seated in the doorframe.
Through the observation window, the cell was empty. The bedding was neatly folded, and even the toothbrush Joker had been issued on his first day was sitting in its cup.
Batman crouched in front of the door and inserted a probe into the keyhole.
The access log quickly unfolded.
The door had not opened once in the past twelve hours.
Robin backed out of the ventilation shaft, his cape covered in dust.
"The dust inside is undisturbed, and the cobwebs aren't broken. If he squeezed out through here, he must be liquid. I suggest Arkham get that on file first."
Batgirl removed the monitoring console's casing.
A tiny signal loop device had been added beneath the circuit board. She snipped one of its wires with tweezers, and the cell footage on the screen immediately began playing backward.
Joker sat on the bed.
Joker lay down.
Joker sat up again.
The entire loop lasted seven minutes and twenty-six seconds.
"Looped footage." Batgirl put the device into an evidence bag. "Installed before eight tonight. The alarm system was delayed by eleven minutes, too. Such a familiar trick."
Across the corridor, several staff members on duty still lay on the floor. Medics fitted them with oxygen masks, then pulled an extremely fine needle from the back of one person's neck.
Traces of sedative remained in the needle.
Batman checked the dosage.
"Unconscious for forty minutes."
"He arranged his pickup at least a day in advance." Batgirl pulled up the duty roster. "Everyone assigned to wing seven tonight had their shifts changed at the last minute. The orders came from the director's office. Someone accessed the director's