You can see how something like that might delay things. And normally this would be an easy call: he got dead for the same reason that many of the Iraqi WMD experts and terrorists-in-residence were disappeared by the Baathists on the eve of the US invasion. But Suleiman was not a mere scientist or low-level agent - he was deep inside the Assad regime. And covering up a covert nuclear program was nowhere near the naughtiest thing that he was involved in:

The UN atomic watchdog's probe into alleged illicit nuclear work in Syria has been delayed because the agency's contact man in Syria was murdered, IAEA chief Mohamed ElBaradei revealed Thursday. "The reason that Syria has been late in providing additional information (is) that our interlocutor has been assassinated in Syria," ElBaradei told a closed-door session of the International Atomic Energy Agency's 35-member board... But according to Arab media reports last month, a brigadier general thought to be the Syrian regime's liaison with Hezbollah in Lebanon was assassinated. The Saudi-owned pan-Arab daily Al-Hayat said the victim was a senior Syrian officer "in charge of sensitive files and closely linked to the Syrian top brass." Al-Bawaba, an Arab news website, named the officer as Mohammed Sleiman, saying he was "Syria's liaison officer with Lebanon's Hezbollah movement." The Lebanese anti-Syrian daily al-Mustaqbal quoted a Syrian news site as saying Sleiman was the head of security at the presidential palace in Damascus and President Bashar al-Assad's "right-hand man."

The rest of the article is about how the IAEA is condemning Israel because there's no evidence that Syria was using the facility to develop nukes. Which will be news to the North Korean nuclear scientists who had the bad luck to be in the building when Israel destroyed it. It would also beg a lot of other questions about why Syria quickly paved over the site or why professional weapons inspectors have no doubts about what the facility was being used for or why it's now public knowledge that Israeli commandos scoped up radioactive soil samples before the warplanes were called in. And the answer to those questions would be: because the IAEA is grossly incompetent.

Regardless: 10 to 1 and pick em, this guy ended up dead for reasons having very little to do with the nuclear facility and very much to do with how he was at the nexus of one of the most dangerous alliances on the planet.

References:
* Contact man's murder delays Syria nuclear probe: IAEA [AFP]
* Washington Post: Several N. Korean scientists hurt in IAF strike in Syria [Ha'aretz]
* Syria Rebuilds on Site Destroyed by Israeli Bombs [NYT]
* Experience With Syria Exemplifies Challenge That Detection Presents [WaPo]
* 'Commandos nearly exposed Sept. 6 Syria strike' [JPost]

Previously:
* The Totally Awesome Israeli Operation That Blew Up Mugniyah Right Under Assad's Nose
* STRATFOR: Syria Massing Troops On The Golan, Israeli Skittishness May Mean War (Plus: Iran's "Final Response" To Israel On October 12)
* Was Syria Actively Building - Or Storing - A Nuke In The Operation Orchard Facility?