In recent weeks, Marco Rubio has tried to hammer GOP frontrunner Donald Trump on Trump University. Multiple reports, however, suggest that this line of attack could backfire on the young Senator, who has financial ties to scandal-plagued for-profit colleges that preyed upon U.S. students. What’s more, Rubio used his stature as a U.S. lawmaker to help the for-profit college operation.

As Bloomberg reported last July: “Florida Senator Marco Rubio’s various political operations have accepted $27,600 in contributions from Corinthian Colleges, a for-profit education chain that shut down in April after a federal investigation found it had engaged in ‘predatory’ practices.”

“In its final year, Corinthian Colleges reportedly said it received $1.2 billion in federal student loans,” Bloomberg reported in April.

“When the U.S. Department of Education last summer slowed down the flow of money to Corinthian because of suspected fraud, Rubio wrote a letter asking the department to ‘demonstrate leniency’ with the company,” the Miami Herald reported in April of 2015.

Bloomberg details how Rubio “went to bat” for his financial booster, which was taking advantage of Rubio’s own constituents:

Senator Marco Rubio of Florida asked the U.S. Department of Education to ‘demonstrate leniency’ toward Corinthian Colleges by permitting the wealthy for-profit company to continue accessing millions of dollars in federal financial aid while it was cooperating with a federal investigation… The top-tier Republican presidential candidate had made his plea in a letter—obtained by Bloomberg Politics—dated June 20, 2014 and addressed to Jim Shelton, the deputy secretary of education, and Ted Mitchell, the undersecretary for post-secondary education.

In his letter, Rubio writes:

It has been brought to my attention that the U.S. Department of Education has recently placed extreme financial constraints on Corinthian Colleges, Inc. by restricting the company’s timely access to federal financial aid…While I commend the Department’s desire to protect our nation’s students from fraudulent and malicious activity by any institution of higher education, regardless of tax status, I believe the Department can and should demonstrate leniency as long as Corinthian Colleges, Inc. continues to expeditiously and earnestly cooperate by providing the documents requested.

Rubio’s spokesman defended the letter by claiming that the Senator wanted to “protect” the thousands of Floridian students from “having their educations disrupted while the investigation was underway.” However, as Bloomberg notes:

Ten months later, the company shuttered its remaining 28 campuses, instantly displacing some 16,000 students just days after it was fined $30 million by the Department of Education for a scheme involving ‘confirmed cases of misrepresentation of job placement rates’ for as many as 947 students. The decision to close shop came after years of federal and state investigations into the company.

According to the Department of Education, “In its investigation of Corinthian Colleges, the Department found numerous causes for concern with practices throughout the Heald College system… for example, one campus classified a 2011 graduate of an Accounting program as employed in the field based upon a food service job she started at Taco Bell in June 2006.”

“In February, the Consumer Financial Protection Bureau announced $480 million in debt relief for students it deemed were ‘harmed by Corinthian’s predatory lending scheme,’” Bloomberg writes.

Yet Corinthian is not the only predatory for-profit school with financial ties to Sen. Rubio. Reports show that Sen. Rubio also received money from the owner of Dade Medical College, Ernesto Perez—who last year pled guilty to illegally making more than $159,000 in campaign contributions. As The Daily Beast reported in November in a piece entitled, “Private College Kingpin Who Bankrolled Florida Pols Surrenders to Feds”:

A well-known Florida donor who gave thousands to prominent pols from Marco Rubio to Debbie Wasserman Schultz turned himself in Tuesday afternoon for allegedly making illegal campaign contributions. The Miami Herald reported that Ernesto Perez, who owns the for-profit Dade Medical College, surrendered on Tuesday and plans to plead guilty for illegally bundling campaign contributions. He will likely serve one day in jail and pay a $200,000 fine… Rubio got a particularly large windfall from Perez. In 2013 he contributed $15,000 to the Florida senator’s political ambitions—$10,000 to his leadership PAC and $5,000 to his principal campaign committee.

The Daily Beast notes that Perez also gave money to Mitt Romney, as well as “$2,500 to disgraced congressman and Rubio pal David Rivera. Perez also donated a total of $3,000 in 2012 and 2013 to former Rep. Mike Grimm (R-NY), who in July was sentenced to eight months in prison for felony tax evasion for underreporting revenues at his restaurant, Healthalicious.”

The Miami Herald reports that students who were victims of Perez’s operation, “say they were left tens of thousands of dollars in debt, with college credits that won’t transfer to traditional schools. Many of the college’s 400 employees say they were stiffed on their final paychecks. Both students and ex-employees have started filing lawsuits.”

The for-profit education industry has surged in Florida. As the Miami Herald reports:

Despite fraud lawsuits and government investigations around the country, Florida’s Legislature continues to encourage the growth of the industry, which says it provides opportunities to disadvantaged students. Lawmakers have increased funding sources and reduced quality standards and oversight. The attorney general in Florida, meanwhile, has been less aggressive than those in some other states in pursuing schools when they skirt laws involving the hundreds of millions they receive in state and federal money… A Herald examination of campaign records since 2008 found that for-profit colleges have contributed more than $1.2 million to state lawmakers and political parties. The Legislature, in turn, passed 15 laws benefiting the industry.

“The for-profit colleges have made their voice heard in Washington as well,” a separate Miami Herald report notes—documenting the industry’s contributions to Florida-based candidates.

For instance, the report notes that the Obama administration has sought to “advance a ‘gainful employment’ rule, aimed directly at for-profit colleges. Under that rule, schools are punished if their graduates have to spend more than 8 percent of their post-graduation earnings on loan repayments. The schools can lose access to federal loans, the industry’s lifeblood.”

Yet “in May [of 2014], seven Florida members of Congress signed a letter to U.S. Education Secretary Arne Duncan urging him not to go through with the gainful employment rule,” the Miami Herald writes.

Sen. Rubio signed the letter. One month later, he sent his separate letter pushing for “leniency” for Corinthian Colleges.

As Bloomberg’s Sahil Kapur observed, Rubio’s previous support for these scandal-plagued institutions seems peculiar given his campaign’s focus on student loans and education: