at the home where he was staying and spirited him away. His ankle monitoring bracelet was later found by the roadside; a week later, he was back in Saudi Arabia — a fact that the authorities in Oregon did not learn until more than a year later.

Federal officials would not discuss their evidence in the case, but they said they believe it shows that the Saudi government helped Noorah flee the country. Investigators suspect that Saudi operatives provided the student with a replacement passport and may also have arranged for him to escape on a private jet, officials of the US Marshals Service said.

But while the police found a trail of clues — including cellphones, a laptop and surveillance camera footage of the black SUV — the StateDepartment has asserted that US officials had "no concrete, credible evidence as to how Mr. Noorah effected his escape." Without an extradition treaty, the department added in a letter to Wyden in February, there was little chance that he could be made to face justice in the United States.

"Are you as disturbed as I am that Saudi nationals have a get-out-of-jail-free card that allows them to commit abuses against children, manslaughter, rape and have no accountability?" Oregon's other US senator, Jeff Merkley, also a Democrat, asked retired Army Gen. John Abizaid last month during a hearing on his confirmation to become the administration's ambassador to Riyadh. "When a person commits a crime in the United States, we shouldn't — because they're an ally that buys a lot of