Agents of Israel's Mossad intelligence service hacked into the computer of a senior Syrian government official a year before Israel bombed a facility in Syria in 2007, according to Der Spiegel.

The intelligence agents planted a Trojan horse on the official's computer in late 2006 while he was staying at a hotel in the Kensington district of London, the German news magazine reported Monday in an extensive account of the bombing attack.

The official reportedly left his computer in his hotel room when he went out, making it easy for agents to install the malware that siphoned files from the laptop. The files contained construction plans for the Al Kabir complex in eastern Syria – said to be an illicit nuclear facility – as well as letters and hundreds of detailed photos showing the complex at various stages of construction, according to the magazine.

At the beginning – probably in 2002, although the material was undated – the construction site looked like a treehouse on stilts, complete with suspicious-looking pipes leading to a pumping station at the Euphrates. Later photos show concrete piers and roofs, which apparently had only one function: to modify the building so that it would look unsuspicious from above. In the end, the whole thing looked as if a shoebox had been placed over something in an attempt to conceal it. But photos from the interior revealed that what was going on at the site was in fact probably work on fissile material.

Early in the morning of September 6, 2007, Israeli fighter jets bombed the complex, located in the desert near the Euphrates river about 80 miles from the Iraq border. The attack, dubbed "Operation Orchard," seemed to come out of nowhere and was marked by a resounding silence from both Israel and the United States afterward.

Israel claimed the incident never occurred. The United States claimed ignorance, but a State Department official suggested the target was nuclear equipment obtained by "secret suppliers."

The Syrians were said to have been building the reactor with help from North Korea. The Israeli military's intelligence unit, known as 8200, was reportedly tipped off to this by the U.S. National Security Agency, which intercepted conversations between Syrian officials at the reactor and North Koreans.

Israel's concern about the facility really kicked into gear when it discovered that Iranian President Mahmoud Ahmadinejad traveled to Syria in 2006, according to Der Spiegel. The magazine alleges that Ahmadinejad promised the Syrians more than $1 billion to hasten their progress on the project.

In early 2007, Iran's former deputy Minister of Defense defected to Turkey and told the CIA that Iran was funding a top-secret nuclear facility in Syria in conjunction with North Korea. Then, days before the Israeli attack on Al Kabir, the Mossad discovered that a ship from North Korea arrived in Syria loaded with uranium materials.

Israel's attack on the facility commenced late in the evening of September 5, when 10 Israeli fighter jets departed from a base in Northern Israel around 11 p.m. and headed west over the Mediterranean. Seven of them turned east to Syria, flying low, and took out a radar station with their missiles. About 20 minutes later they released their bombs on Al Kabir.

Afterward, Israeli Prime Minister Ehud Olmert reportedly sent a message to Syrian President Bashar Assad through Turkey saying no further hostilities were planned.

Israel, Olmert said, did not want to play up the incident and was still interested in making peace with Damascus. He added that if Assad chose not to draw attention to the Israeli strike, he would do the same. In this way, a deafening silence about the mysterious event in the desert began. Nevertheless, the story did not end there, because there were many who chose to shed light on the incident – and others who were intent on exacting revenge.

Assad maintains that the facility was a conventional military installation. But Der Spiegel reports that in June 2008, a team of experts from the International Atomic Energy Agency analyzed soil at Al Kabir taken after the bombing and found traces of uranium that were "of a type not included in Syria's declared inventory of nuclear material." Assad says the Israelis dropped the samples from the air when they bombed the facility in order to frame Syria.

Photo: Aug. 5, 2007 satellite image of suspected nuclear reactor site in Syria a month before it was bombed. (AP Photo/DigitalGlobe)