Donald Trump used his private foundation — funded largely by outsider contributions — to build relationships with social conservative groups ahead of his 2016 presidential bid, an examination by Real Clear Politics published Tuesday found.

In one case, the Trump Foundation may have violated IRS rules by donating to a not-for-profit allowed to engage in a political activity — and thus subject to tougher regulations regarding incoming contributions — as opposed to a traditional charity. The other transactions highlighted by Real Clear Politics reveal a pattern starting in 2011 of Trump speaking at right wing groups’ confabs around the same time the Trump Foundation was making donations to their non-profit affiliates, though the RCP report stopped short of alleging an explicit quid pro quo.

“He was politically active starting in 2011,” a source with ties to Trump told RCP, adding that around that time Trump “started to make strategic donations.”

Trump Foundation tax filings between in 2011 and 2014 showed that it donated up at least $286,000 to noteworthy conservative or policy groups, RCP reported. Often times, the contributions were from Trump’s foundation to the charity arms of the social conservative groups. However, Trump Foundation tax returns from 2013 show a $10,000 contribution to The Family Leader — a 501(c)(4) that is allowed to engage in limited political activity and thus receives more scrutiny — rather than to the group’s 501(c)(3) charity affiliate the Family Leader Foundation, according to RCP.

“There’s a mistake somewhere,” Rosemary Fei, a partner at the Adler & Colvin law firm in San Francisco, who specializes in charity law, told RCP. “It might be a really substantive mistake, or it could just be a reporting error or sloppiness. But improper reporting is still a violation of tax law. That’s something the IRS would look at.”

Even in instances where the Trump Foundation probably did not violate charity tax law, the foundation’s transactions paint a picture of how Trump made inroads with the social conservative movement — which had reason to be skeptical of the flashy New York billionaire — as he laid the ground work for his campaign for the GOP nomination.

The RCP report comes as the Trump Foundation is under investigation by the New York Attorney General’s office, which ordered last week that it cease its fundraising activities because it lacked the proper certification to solicit contributions. Trump himself stopped donating to the foundation after 2008, according to tax filings, and its coffers have since been filled outside contributors.