To find out more about how a Chinese national gained access to Arizona's terror center, read last week's exclusive piece from ProPublica and The Center for Investigative Reporting.

Xunmei Li, the Chinese immigrant and businesswoman who played a role in a large-scale security lapse inside the Arizona Counter Terrorism Information Center, lost her U.S. citizenship last week and likely faces exile from the country.

Federal Judge David Campbell ruled that Li's 2009 conviction for immigration fraud, combined with evidence that she was knowingly married to two men at once, is sufficient cause to denaturalize her. Li, 44, lied to immigration officials about how many times she'd married and whether she has children while applying for citizenship a decade ago. She denied being a mother despite having two U.S.-born daughters.

The order against Li is the latest chapter in the murky, long-buried story of how a Chinese national came to work inside the counter terrorism center in Phoenix. Lizhong Fan, a computer programmer from Beijing, spent five months in 2007 working with confidential records, including Arizona's database of five million driver's licenses. Fan abruptly left for China with computer equipment, potentially holding reams of sensitive data.

Li, who emigrated to the U.S. from Shanghai in 1994, has said she was the person whose recommendation led to Fan working inside the intelligence center. Li said she suggested Fan as a candidate to work on a facial recognition program owned and operated by a small security company called Hummingbird Defense Systems. Li was the girlfriend of the company's chief executive, Steve Greschner.

The Maricopa County Sheriff's Office hired Hummingbird to set up the facial recognition system, and then persuaded officials to install the system in the intelligence center. The center, formed in 2004, allows more than 20 police agencies to work together to thwart possible terror attacks.

Arizona state and local officials did not disclose the possible breach at the center to the public. A joint investigation by ProPublica and The Center for Investigative Reporting detailed the security failure in an August 26 story.

It remains unclear how closely law enforcement looked into the incident or whether it moved to prevent future breaches. The FBI opened a probe shortly after Fan disappeared in June 2007, according to records and a former federal investigator, but the bureau hasn't made its findings public. The Arizona Department of Public Safety, which operates the intelligence center, has refused to comment.

Federal investigators came to worry that Li was a spy for China, said Paul Haney, a retired U.S Immigration and Customs Enforcement agent. Haney's criminal immigration investigation of Li led to her fraud conviction and, ultimately, the denaturalization case.

The government has never filed espionage or national security charges against Li. She did not respond to calls for comment this week, but has repeatedly denied any involvement in espionage.

"Absent a confession, we can only speculate," Haney said of whether Li served as a Chinese spy. "Maybe she's telling the truth and she's not an operative. I don't know."

Don Bivens, Li's lawyer, said in a statement that he cannot understand why government lawyers took such severe action against his client, "who in our view simply made mistakes on her naturalization application that are commonly made by hundreds of immigrants every day."

Patricia Corrales, a former U.S. Immigration and Customs Enforcement attorney who was involved with many denaturalization cases in her career, said revoking citizenship has been used in situations that involved national security concerns, particularly when it involves false testimony, without disclosing secrets or such suspicions.

"Now, most people think, "Bigamy, what's the big deal with that?" said Corrales, who is now an immigration attorney in Southern California. "We want only people who deserve to be U.S. citizens in this country to have that status. If you're going to lie about your kids what else are you going to be lying about?"

Christopher Dempsey, a U.S. Justice Department attorney who represented the government at trial, referred calls for comment to the Justice Department.

A Justice Department spokeswoman said the government is pleased with the court's decision and the order "speaks for itself."

The U.S. Attorney's Office has said it intends to start deportation proceedings against Li. She can appeal her denaturalization. Bivens, Li's lawyer, declined to comment on whether his client will continue to fight for her citizenship.

Judge Campbell scheduled a hearing for later this month to establish how to proceed with Li's denaturalization.

Andrew Becker, a reporter at The Center for Investigative Reporting, contributed to this report.