Robert Blagojevich testified in his own trial that representatives for Congressman Jackson offered to raise about $6 million for his brother's campaign fund in exchange for an appointment to the Senate. Jackson has always denied those allegations, saying he has done nothing illegal.
But, Robert Blagojevich has written all 10 members of the House ethics panel, offering to testify before them.
It has been nearly three years since former governor Rod Blagojevich was arrested and indicted for trying to sell an appointment to the Senate seat vacated by President Barack Obama. One of the reported interested parties was Congressman Jesse Jackson Junior, who testified against Blagojevich in his second trial.
Prosecutors have never suggested publicly that the congressman did anything wrong, but his colleagues in congress are still considering that possibility. And, if the House ethics committee takes up the case, the ex-governor's brother is more than willing to help out.
"I believe Congressman Jackson has got some questions to answer that he's never been asked," said Robert Blagojevich in a telephone interview.
Legal experts say Congressman Jackson could face serious consequences if the ethics committee finds wrongdoing. They could censure him. Or, based on the findings, it could lead to criminal charges, including the possibility of perjury, since Jackson could be compelled to testify under oath.
"Not only is this classic quid pro quo, you help me and I'll help you, this goes far beyond that and could be even subject to a criminal investigation," said Doug Godfrey of the Chicago-Kent Law School.
As a member of his brother's campaign staff, Robert Blagojevich also faced charges in the case which were later dropped.
But throughout the proceedings he has made a concerted effort to avoid the attention that his brother seemed to revel in. That makes Robert Blagojevich's willingness to testify against Congressman Jackson all the more significant.
"I feel I have a responsibility to go tell the committee that's possibly investigating that specific act that I could give them information that could helpful if they're seeking the truth to find the truth," Robert Blagojevich said.
"He hasn't sought out the limelight, so he obviously feels very strongly about this," Godfrey sad.
Robert Blagojevich tells ABC7 he has spoken with the ethics committee chief of staff who said they would take his offer to testify under advisement.
So far, Congressman Jackson has offered no response.