Jackson spokesman Rick Bryant has said relatives requested Jackson's location be kept private, and his family has been unusually reticent on the issue. His wife has said little and Jackson's civil rights leader father, the Rev. Jesse Jackson Sr., has called it a private issue and repeatedly declined to give details.
A House Ethics Committee investigation is pending over allegations that Jackson discussed raising money for Blagojevich's campaign so the then-Illinois governor would appoint him to President Barack Obama's vacated U.S. Senate seat. Blagojevich is serving a prison sentence for corruption. Jackson has denied those claims.
Jackson also allegedly directed a fundraiser, Raghuveer Nayak, to buy plane tickets for a woman described as Jackson's "social acquaintance." Jackson and his wife have called that a personal matter.
Days before Jackson announced the medical leave, Nayak was arrested and pleaded not guilty to unrelated medical fraud charges. At Blagojevich's 2010 corruption trial, prosecutors said another Blagojevich fundraiser was ready to testify that Jackson instructed Nayak to raise money for Blagojevich's campaign to help him secure the Senate seat. The same witness later testified he attended a meeting with Jackson and Nayak.
Jackson was not charged and has repeatedly denied wrongdoing.
Jackson faces a Republican and independent candidate in November, though he's widely expected to win re-election. He first won office in a 1995 special election and has easily won each race since. Jackson's district includes parts of Chicago and some suburbs.
Associated Press writers Donna Cassata in Washington and Jason Keyser in Chicago contributed to this report.
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