Information about the deportation case was disclosed and confirmed by two separate sources, one of them a federal law enforcement official. The information they made available is known to officials in the federal government, but the AP could not establish whether anyone at a political level in the Bush administration or in the McCain campaign had been involved in its release.
Onyango's refusal to leave the country would represent an administrative, non-criminal violation of U.S. immigration law, meaning such cases are handled outside the criminal court system. Estimates vary, but many experts believe there are more than 10 million such immigrants in the United States.
The AP could not reach Onyango immediately for comment. No one answered the telephone number listed in her name late Friday. It was unclear why her request for asylum was rejected in 2004. The Obama campaign declined to comment late Friday night.
Onyango is not a relative whom Obama has discussed in campaign appearances and, unlike Obama's father and grandmother, is not someone who has been part of the public discussion about his personal life.
A spokeswoman for U.S. Immigrations and Customs Enforcement, Kelly Nantel, said the government does not comment on an individual's citizenship status or immigration case.
Onyango's case - coming to light just days before the presidential election
- led to an unusual nationwide directive within Immigrations and Customs Enforcement requiring any deportations prior to Tuesday's election to be approved at least at the level of ICE regional directors, the U.S. law enforcement official told the AP.