The Saudi government allowed the woman, who was under a federal grand jury subpoena related to the terrorism investigation, to leave the United States, enraging American investigators.
The report, first seen in The Washington Post on Wednesday, is the latest indication that some U.S. officials are disappointed with Saudi Arabia's cooperation in their drive to thwart terrorism.
The woman, Maha Hafeez Marri, is the wife of Ali S. Marri, a man who has been charged with lying to authorities investigating possible terrorist activity and is in federal custody.
Marri was first charged with credit card fraud and then charged with lying to investigators about a trip to the United Arab Emirates and calls to a man in the UAE who allegedly handled expenses for the Sept. 11 hijackers.
The family had been living in Peoria, Ill., at the time of the husband's arrest. When Ali Marri was booked in late 2001, the Saudi embassy brought Maha Marri and the rest of the family to Washington. Ali Marri has pled not guilty to both charges and is being held without bail in New York.
The Post reports federal officials say Maha Marri's passport, as well as those of the couple's five children, were seized when her husband was arrested.
She was subsequently subpoenaed to appear before a grand jury, but it is not clear when. No testimony had been scheduled.
Marri left on Nov. 10. The next day, the embassy informed the State Department she had left, saying she would remain available for questioning.
"It was a big shock to our guys. All of a sudden, she's gone. That's what upset the troops," a law enforcement official told the Post.
In a statement issued late Wednesday night, the Saudi embassy said the Riyadh government has "assured the United States in a formal communication that Mrs. Marri will be made available to U.S. authorities, should they wish to interview her."
The spokeswoman at the Federal Bureau of Investigation field office in Washington was not immediately available for comment.
The Saudi statement also defended the embassy's decision to issue passports to Mrs. Marri and her children.
During a 10-month period last year, with no contact from the FBI, "the Saudi Embassy made numerous inquiries to the U.S. government about allowing her to return to her family in Saudi Arabia.
"Mrs. Marri had no money or means of economic support. She was suffering from Graves disease and was in need of medical attention. Her children could not attend schools. To prevent Mrs. Marri from rejoining her family for such a long period of time is unreasonable and unjust."
The State Department, however, told the Post that it did not give the Saudis a green light to issue the passport.
Saudi Arabia has been under pressure since the start of the America's post-Sept. 11 fight against terrorist groups. Fifteen on the 19 hijackers were Saudis, and some Saudi charities have been accused of funding terrorism.
In November, the Saudis were embarrassed by reports Princess Haifa al-Faisal, wife of the Saudi ambassador to the United States, may have indirectly helped two of the men who participated in the attacks in New York and Washington.
The princess sent monthly checks to a Saudi woman living in the United States. Saudi officials said she was the wife of Osama Basnan, who along with Omar al-Bayoumi is believed to have lent financial support to two of the Sept. 11 hijackers, Khalif al-Mihdhar and Nawaf al-Hazmi, while they lived in the United States.
Saudi officials confirmed that some of the princess' donations ended up with al-Bayoumi's family. But they defended the charitable giving, saying it is the habit of Saudis in the United States to support each other.
The incident led Saudi Arabia to establish stricter controls on charitable donations. But the government contends it has been a full partner in the war on terror.