CHICAGO, Nov. 21 (UPI) --
U.S. Rep. Jesse Jackson Jr., D-Ill., plans to resign Wednesday, Jackson's brother Jonathan said.

Jackson, who has been on medical leave since June has been receiving treatment at the Mayo Clinic in Minnesota for bipolar disorder. WBBM-TV, Chicago, said he is staying with an unidentified relative.

Jackson, 47, also has been reported under investigation by the U.S. attorney's office for misusing campaign funds. Reports indicated he was in plea negotiations.

WBBM said a letter is being sent to staffers and will be submitted to House Speaker John Boehner, R-Ohio, later in the day.

The resignation would be the second in the 2nd Congressional District. His predecessor, Mel Reynolds, was convicted of engaging in sex with a minor and other charges.