had vanished, the officials added.

The Saudis' early warning system began to operate more frequently and sometimes more aggressively as the number of Saudi students in the US grew

The Saudis' early warning system had long protected members of influential families and other Saudi visitors to the United States. In order to safeguard the kingdom's image, Saudi diplomats often hurried to repatriate businessmen, students or others who got into trouble, preferably before any legal action could be taken against them.

"There was a practice if somebody got into trouble where they called the embassy and the embassy would come and scoop them up before charges were filed," Smith said. "The Saudis didn't want any embarrassment. They would take them out in the middle of the night."

National security officials said that systembegan to operate more frequently and sometimes more aggressively as the number of Saudi students in the United States grew. In one such case, Saudi officials put up $65,000 to cover the $650,000 bond of an 18-year-old student, Ali Alhamoud, after he was jailed on charges of raping a young woman in a small town near the Oregon coast. Within hours after he was bailed out of jail, Alhamoud boarded a plane and flew home, court records show.

"It's essentially a rendition of their own citizens," said David Rubincam, who took over as the FBI's legal attache in Riyadh in 2008, just as the scholarship program was starting to grow. "There were a lot of less-visible situations where they would pull a student back. The more students, the more