The solution was to use a gas that had a broad range of explosive limits. He had played with a gas called Silane — a silicon analog of methane. Its explosive limits were between 1.5 and 98 %. The problem was that it stunk so badly that it would make you throw up and would spontaneously explode if you so much as looked at it cross-eyed. It wasn't something that you could find easily, though lots of it was made for various industrial processes ranging from anti-graffiti coatings to a potential candidate for a rocket engine that could work on Mars as it could use carbon dioxide as an oxidizer.
The next candidate on the list was so much easier to work with and could be found anywhere in the world, which made working with something like Silane a non-starter. With explosive limits of 2.5 to 81 percent, acetylene was the perfect choice. You could get as much as you wanted at any welding supply shop, it spread throughout an area equally, being about ten percent lighter than air so you didn't have to worry about it diving into the basement or other low-lying areas, and almost anything could set it off.
The attack plan consisted of several layers. He had two tanks of acetylene on a welding car and a manifold he had constructed to connect them together. A hundred foot of hose along with an ALA-17 Flare Cartridge at the end. That particular model was designed for self-protection against heat seeking missiles in the B-52 and he had picked up a crate of them at a military surplus store quite cheap. They were electrically fired and ejected a very hotly burning magnesium/Teflon pellet which would do nicely in setting off his acetylene gas/air explosion.
The flare was connected via wire back to the tanks and would be fired when the level of the acetylene dropped to a certain point — one contact was wired to the gauge needle and the other to a pin that the needle would contact when the gas got to a certain level — a variation on the simple clock bomb. He had tried using gas detectors tied to an electric match, but they were not only expensive, but very unreliable. So, he went back to something tried, true, simple and cheap.
There was a camera on the back of the building. Crouching out of its view point as it panned the area, he calculated how long it would take to come back around. Sure he could have defeated it several different ways, but the instant something went wrong with it, someone would come looking and may discover him and his equipment.
He wasn't a burglar, but he had more than an amateur level of ability in defeating alarm systems. The security system around the police department garage didn't appear too sophisticated and was comprised of what appeared only to be cameras on a rotating sweep. No motion detectors, IR alarms, pressure plates. This made sense as the building really didn't protect very much, just some equipment. Who would be stupid enough to steal an outdated squad car and what would you do with it once you had it?
The camera panned and as soon as it was out of range, he crawled through the hole he cut in the bottom of the fence and dragged the hose connected to the acetylene tanks along. The camouflage job on the hose wouldn't pass close scrutiny, but it would be more than enough to conceal it from the camera.
He made his way up to the building and stood under the camera mount. Incidentally, it was right next to the exhaust fan housing. Prying the vents open, he slid his hands in and cut the wire to the motor. It might want to turn on, but now couldn't.
Then he stuffed the hose in as far as he could, being careful with the flare taped to the end. Of this operation, that was the only thing that really scared him — that damn flare going off. Magnesium burned at half the temperature of the surface of the sun and he didn't want to be anywhere near it when it went off.
He taped the hose to the side of the building, and then waited for the camera to pan again. Then he made his way to the fence and crawled back through. He looked at his work to see if it would be detectible by the camera. In his best judgment, it wouldn't be — the only way that someone could find it would be to trip over the damn thing.
Closing the hole in the fence only took a couple of minutes — he wasn't looking for undetectable as everyone would soon be able to figure out what had happened, he just wanted to pass a distant look.
Then he connected the firing device to the battery. This was always the point where his pulse pounded in his ears — the most dangerous part of the entire operation was providing power to a device. Most explosives were reasonably stable, but detonators were just looking for an excuse to go off, and often did, causing all sorts of problems, the least being the loss of fingers. That's why old demolition men often were a few digits short.
Nothing happened, which was good. He let out a sigh and turned the valves to the acetylene tanks wide open and then half a turn back. By his calculations, the building should be at about fifty percent full with gas when the flare went off. Should make for a very interesting explosion to say the least.
Checking his work again, he nodded and slipped into the night.
FBI Special Agent Jeff Silver was at the top of his game and he knew it. A patrol car had seen Leo Marston's truck parked by the hotel and from there, it had been simple to pick him up.
They found a silenced pistol on the night stand, a laptop that the technical services guys were trying to break into and some personal possessions. They had also towed back his truck to the impound yard and were doing a complete inventory of it. The most obvious finding was the rifle — unlike anything he had ever seen before with a very heavy barrel, huge scope and strange stock. The HRT sniper had looked at it and told him that it was one hell of a rifle and who knew how accurate it could be — but the potential was almost limitless, especially when they found the hand-loaded ammunition and Leo's rifle log book.
There were other secrets in the truck and it would probably require a complete disassembly of the vehicle to pry them out — they had already found two hidden compartments, one containing a quantity of gold coins and bullion and the other stuffed with old series $100 bills.
The only sticking point was that Leo hadn't said one word. He had complied with all of their commands, but was strangely silent. Nothing they said could get him to say anything.
Silver looked through the one-way window of the interrogation room at the shackled man seated at the desk. He looked to be a statue that sat motionless for hours.
They had taken all of his clothes as evidence and he was dressed in an orange jump suit that was at least two sizes too big, but he still seemed to fill it with an eerie presence, like a snake waiting to strike.
Usually, they tried to make people in the interrogation room comfortable by leaving them unshackled and uncuffed. But the search of Leo's possessions had revealed a ceramic razor blade and plastic handcuff key taped inside his belt, so no one wanted to take any chances.
He took a sip of his rapidly cooling coffee. Nodding at the federal prosecutor, Becky Miller, he opened the door to the interrogation room, and hoped he could get Leo to talk.
Tyrannicide was, if a piece of software could be ascribed with emotions, satisfied with its work. Most of the goals of this part of the operation had been met with some minor setbacks that were to be expected in such a complex endeavor.
Employees of all levels of federal, state, county and city government were resigning in droves in the Denver area. That only changed their status slightly as far as their placement on the assassination went — they would get their just deserves at some point in the future, but now, with limited resources, the more prominent targets must be dealt with first.
It prepared, based on news reports and public records, another list of targets.