Washington (CNN) -- The House Ethics Committee announced Friday that it is continuing to investigate whether Rep. Jesse Jackson Jr. or an "emissary" engaged in fund-raising efforts for then-Illinois Gov. Rod Blagojevich in exchange for the U.S. Senate seat vacated by President Barack Obama.
The panel said it found "probable cause" to believe that Jackson instructed one of his supporters to raise the money.
"If this 'emissary' acted either at the direction of Representative Jackson or with his knowledge or acquiescence, Representative Jackson may have violated federal law and House rules," the committee said in a written statement.
The Office of Congressional Ethics said in 2009 that transcripts of recordings of Blagojevich contain statements that a Jackson emissary offered to raise money for the former governor and provide "money up front."
The ethics committee is also investigating whether Jackson's offices mishandled federal money to construct a "public campaign" meant to secure his election.
"In doing so, Representative Jackson may have violated federal law and House rules concerning the proper use of the member's representational allowance," the statement said.
Jackson has maintained his innocence and pledged to continue to cooperate with authorities.
"I did nothing illegal, unethical or inappropriate in that pursuit, and I believe that is what the Ethics Committee will conclude at the end of this process," he said.
Meanwhile, federal prosecutors have announced that they are asking Blagojevich be sentenced to 15 to 20 years in prison.
He was convicted of corruption in June, when a jury returned 17 guilty verdicts against him.
Sentencing is scheduled for Tuesday.