Rangel's office declined to comment. But it released a statement saying: "Having now learned that the trip eimbursement was made erroneously, Congressman Rangel will of course refund the funds in question."

Morgan said the controversy surrounding Rangel has given a boost to his campaign.

“Yes, more people have been quietly supporting my candidacy,” Morgan said, adding that momentum has been building for some time. "People have been clamoring for a while that we just need a change and this ethics stuff has only reinforced a notion that Mr. Rangel has gotten further and further out of touch with the district and its priorities," he said.

Morgan noted that Rangel has spent four decades in office.

"Frankly, with all of his experience, how did he even put himself in that situation? He should have known better," he said. "It just shows a lack of judgment."

Still, Morgan said the controversy won't hand him a win in the Democratic primary. "I think that I will have to do the work," he said.

He has a steep hill to climb – Morgan had less than $25,000 cash on hand at the end of the year. Rangel had some $770,000, according to his campaign finance report.

Updated at 5:45 p.m.