Neighbours gasped when authorities showed them photos of the inside of the Southern California home: Crates of grenades, mason jars of white, explosive powder and jugs of volatile chemicals that are normally the domain of suicide bombers.
Prosecutors say Serbian-born George Jakubec quietly packed the home with the largest amount of homemade explosives ever found in one location in the US and was running a virtual bomb-making factory in his suburban neighbourhood. How the alleged bank robber obtained the chemicals and what he planned to do with them remain mysteries.
Now authorities face the risky task of getting rid of the explosives. The property is so dangerous and volatile that that they have no choice but to burn the home to the ground this week in a highly controlled operation involving dozens of firefighters, scientists and hazardous material and pollution experts.
Authorities went into the home after Jakubec was arrested, but encountered a maze of floor-to-ceiling junk and explosives that included 13 unfinished shrapnel grenades.
Bomb experts pulled out about nine pounds of explosive material and detonated it, but they soon realized it was too dangerous to continue given the quantity of hazardous substances. A bomb-disposing robot was ruled out because of the obstacle of all the junk Jakubec hoarded.
That left only one option — burn the home down.
San Marcos Fire Chief Todd Newman acknowledges it is no small feat: Authorities have never dealt with destroying such a large quantity of dangerous material in the middle of a populated area, bordered by a busy eight-lane freeway.
"This is a truly unknown situation," said Neal Langerman, the top scientist at the safety consulting firm, Advanced Chemical Safety in San Diego. "They've got a very good inventory of what's in there. Do I anticipate something going wrong? No. But even in a controlled burn, things occasionally go wrong."
He said the burning of the house would provide "an amazing textbook study" for bomb technicians in the future.
San Diego County authorities plan to burn the home Wednesday but need near perfect weather, with no rain, no fog, and only light winds blowing toward the east, away from the city. They have warned residents in the danger zone that they will be given less than 24 hours notice to evacuate their homes for a day, and that nearby Interstate 15, connecting the area to San Diego, will be closed.
Govenor Arnold Schwarzenegger has declared a state of emergency, and hospitals will be on standby in case there is a rash of people getting sick, Newman said.
Some 40 experts on bombs and hazardous material from across the country and at least eight national laboratories are working on the preparations.
They have analysed wind patterns to ensure the smoke will not float over homes beyond the scores that will be evacuated. They have studied how fast the chemicals can become neutralized under heat expected to reach 1,800 degrees Fahrenheit (1,000 Celsius) and estimate that could happen within 30 minutes, which means most of the toxins will not even escape the burning home, Newman said.
The county has installed 18 sensors that will measure the amount of chemicals in the smoke and send the data every two minutes to computers monitored by the fire and hazardous material departments.
Experts also have mapped how far the plume will travel and predict it will not go beyond Interstate 15. They calculate that if there is an explosion, it would probably throw the debris only about 18 metres.
"It certainly would not be a detonation that would level a neighbourhood," Newman said.
Crews are clearing brush, wood fences and other debris that could cause the blaze to spread beyond the property in a region hit by wildfires in recent years. They also are building a five-metre-high fire-resistant wall with a metal frame between the property and the nearest home, which will be coated with a fire-resistant gel.
Firefighters, who will remain 90 metres away, are placing hose lines in the front and back yards and will have a remote-controlled hose aimed at the nearest neighbour's home. Ambulances also will be parked nearby.
The Sheriff's Bomb Squad will ignite the fire remotely with a sequenced series of incendiary devices, Newman said.
Air pollution control experts have installed a portable weather station on a nearby fire station that will tell them immediately when the weather shifts, while authorities observe the burn from helicopters overhead.
Afterward, officials will monitor the air and groundwater for toxins. Hazardous material crews will be brought in to remove the top layer of dirt on the half-acre property, possibly digging down as much as 15 centimetres.
"It'll be a tedious process that will probably take a long time," Newman said.
It also will be expensive, he said, although no one knows yet how much the price tag could run or who will pay for it. They could not be reached for comment.
Prosecutors said the chemicals in the house include hexamethylene triperoxide diamine (HMTD), erythritol tetranitrate (ETN), and pentaerythitol tetranitrate (PETN), which was used in the 2001 airliner shoe-bombing attempt. The home has been declared a public nuisance and therefore the county does not have to reimburse the owners, who were renting the house to Jakubec.
Authorities also found a grenade mold, a bag with pieces of metal, a jar with ball bearings, three wireless doorbells with remotes, molds of human faces, handguns and a blue Escondido police shirt, among other items, according to court records.
Jakubec is in federal custody after being indicted by a federal grand jury on charges related to making destructive devices and robbing three local banks.
The federal grand jury alleges that Jakubec made nine detonators and 13 grenade hulls containing high explosives. They were discovered in the home after a gardener was injured in November in a blast that occurred when he stepped on chemical residue in the backyard, authorities said. Mario Garcia, 49, suffered eye, chest and arm injuries.
Little is known about Jakubec, a 54-year-old unemployed software consultant. His lawyer could not be reached for comment. His estranged wife has told the San Diego Union-Tribune that he became increasingly unstable since losing his job several years ago.
Neighbours say the couple did not draw attention.
Since the incident, Patti Harrison has stared at the home on the knoll in front of her own and wondered what went through Jakubec's mind.
"When I saw those pictures at the meeting with authorities I thought 'oh my goodness, that's just crazy,"' she said.
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