The criminal trial of U.S. Rep. Chaka Fattah focused Tuesday on the problems of his son.

A top Drexel University lobbyist, Brian T. Keech, testified about the tuition and academic woes of Chaka "Chip" Fattah Jr. that three times prompted Drexel to put him on a payment plan.

The younger Fattah repeatedly stopped paying his college bills, and federal prosecutors allege that his father solved the problem by stealing from his campaign fund to pay Drexel.

Chip Fattah's tuition became a headache for the lobbyist when the younger Fattah came to him after Drexel barred him from attending classes because of $30,000 in unpaid tuition. On the stand, Keech called his dealings with the son "a bit unusual."

Taking pains to keep two successive university presidents in the loop, Keech said, he helped work out payment plans for Fattah. The first called for Fattah to pay $400 a month toward his debt, and permitted him to resume his classwork toward a business degree.

Within two years, though, Fattah had fallen behind again, prompting the university to use a collection agency until he agreed to a second repayment schedule.

In 2011, Fattah was put on a third plan, but fell behind once more.

At one point, Keech said, he spoke about Chip Fattah's tuition and academic difficulties with the congressman, who he said sought no favors for his son.

In the complex indictment against Fattah, 59, a veteran West Philadelphia Democrat, prosecutors say he conspired with political consultant Gregory Naylor, his fomer chief of staff, to route $22,263 from two campaign funds to resolve his son's college finances. The money went directly to Drexel and the student lender Sallie Mae, from which the son had borrowed money for college.

Naylor covered up the crime by falsely declaring that the younger Fattah had worked for his consulting firm, the indictment says. Naylor and another political consultant, Washington operative Thomas Lindenfeld, admitted their guilt in 2014 and agreed to cooperate with prosecutors in the case against Fattah and the four other defendants now on trial with him.

Prosecutors say the tuition scam was only one element in a constellation of crimes in which they say Fattah stole $600,000 in government grants and charitable funding, and washed it through two compliant nonprofits and Lindenfeld's business to pay off a massive illegal campaign loan taken out to finance his losing 2007 mayoral bid.

Lindenfeld took the stand last week; Naylor is expected to testify soon. He testified as a prosecution witness last fall in the case against Chip Fattah.

The younger Fattah, 33, was found guilty of bank and tax fraud and is serving a five-year sentence in a federal prison in Michigan. He was sentenced by U.S. District Judge Harvey Bartle III, who is presiding over his father's trial.

Chip Fattah has never obtained a college degree.