He cleared his head. So close and yet so … No, he was not down for the count. Deactivating the alarm would have been enormously helpful, but he had not exhausted his backup plans. The door was alarmed. Accept it. If the alarm system did not detect that it had been opened, however, it would not go off. With the help of a penlight, Janson scanned the dark-stained door until he saw the tiny screws on the topmost section: evidence of the contact switch. Within the door frame, the contacts of a ferrous-metal switch were kept together—the circuit was kept closed—by a magnet recessed in the top of the door. As long as the door was shut, the magnet would keep a plunger within the door frame depressed, completing the electric circuit within the switch unit. Janson withdrew a powerful magnet from his knapsack and, using a fast-drying cyanoacrylate adhesive, fastened it to the lower part of the door frame.

Then he went to work on the door lock. More bad news: there was no keyhole. The door was opened by means of a magnetic card. Could the door simply be forced? No: he had to assume a heavy steel grid inside the wooden door and a multiple door-frame-bolt locking system. You had to ask a door like that to open. Unless you meant to take down part of the building, you couldn’t force it to.

It was an eventuality he had prepared for; but again, with his rough-and-ready tools, the chances of success were far less than with the kind of instruments he was accustomed to having at his disposal. Certainly, his magnetic picklock was not an impressive-looking piece of equipment, having been jury-rigged with electrical tape and epoxy. He had removed the core of the solenoid and replaced it with a steel rod. At the other end of the rod, he had attached a thin rectangle of steel, which he had cut from a tin of butter cookies using heavy-duty scissors. The electronic part—a random noise generator—was a simple circuit of transistors he had extracted from a RadioShack cell phone. Once he connected a pair of AA batteries to the apparatus, a quickly oscillating magnetic field was created: it was designed to pulse at the sensors until they were activated.

Janson inserted the metal rectangle in the slot and waited. Slow seconds ticked by.

Nothing.

Swallowing a gorge of frustration, he checked the battery contacts and reinserted the metal card. More long seconds ticked by—and suddenly he heard the click of the lock’s own solenoid being activated. The door’s bolts and latches were swiftly retracted.

He let out his breath slowly, and opened the door.

As long as the house was occupied, any internal photoelectric alarms would be deactivated. If he’d guessed wrong, it wouldn’t take long to find out. Janson quietly closed the door behind him and, in the gloom, proceeded down a long hall.