An NBC News analysis of hundreds of foreign fighters who died in Iraq over the last two years reveals that a majority came from the same country as most of the 9/11 hijackers — Saudi Arabia.
Among the suicide bombers was Ahmed al-Ghamdi, a one-time medical student and son of a Saudi diplomat. In December 2004, he climbed into a truck in Mosul and blew himself up.
On an Internet video, another Saudi says goodbye to his mother, then drives an ambulance full of explosives into a building.
They are among more than 400 militants from 21 countries whose deaths were celebrated on Islamic Web sites over the last two years.
"By far the nationality that comes up over and over again is Saudi Arabia," says Evan Kohlmann, an NBC News terrorism expert.
The NBC News analysis of Web site postings found that 55 percent of foreign insurgents came from Saudi Arabia, 13 percent from Syria, 9 percent from North Africa and 3 percent from Europe.
The U.S. military also says Saudi Arabia and Syria are the leading sources of insurgents. An Army official provided a list of the top 10 countries to NBC News but would not release the numbers of foreign fighters from each. The top 10, alphabetically, are: Egypt, Iran, Jordan, Lebanon, the Palestinian territories, Saudi Arabia, Sudan, Syria, Tunisia and Yemen.
"You have some from poor families, some jobless," says Kohlmann. "You also have individuals that come from wealthy families, that come from a life of privilege and substance and material goods and material wealth."
Why do they go?
Saudis captured in Iraq say it's because of pictures on Arab television network Al-Jazeera.
"We saw the Americans massacring the Iraqis," says one Saudi prisoner in Iraq via translation.
Radical Saudi clerics urge them to go to Iraq to kill Americans.
"I read the communique of the 26 clerics," says another Saudi prisoner in Iraq.
Saudi officials insist they've made great strides in the war on terror and are doing everything possible to stop men from going to Iraq.
"When we have the evidence, we arrest those people and we put them in jail and take them to court because this is illegal," says Mansour al-Turki, spokesman for the Saudi Ministry of the Interior.
Monday night, a senior Saudi official expressed skepticism — especially about the Internet eulogies of slain fighters — saying he won't believe that many Saudis have died in Iraq until he sees the DNA evidence to prove it.