Adding to the list of Trump’s questionable financial dealings, Robert Mueller is investigating a $150,000 donation to Trump’s foundation by a Ukrainian steel magnate, the New York Times reported Monday. The donation was made by Ukrainian billionaire Victor Pinchuk in return for the then-GOP candidate delivering a 20-minute address via video link to a conference in Kiev. The timing of the transaction in September 2015 raises questions about whether the money was, in essence, a thinly veiled alternative campaign donation in an attempt to curry favor with the Republican frontrunner for president.

Mueller’s reported interest in the transaction jibes with the special counsel’s reported focus on Trump’s murky foreign financial links, even those beyond Russia. Trump personal lawyer Michael Cohen orchestrated the payment for the appearance to the pro-Europe Yalta European Strategy conference. The Guardian, reporting on the event in Kiev at the time, described it as a “bizarre appearance” by Trump. “Trump’s video link was subject to a delay of several seconds, which appeared to confuse Trump,” according to the Guardian. “The audience, who were enjoying a four-course dinner during the video link, occasionally broke into laughter at his responses.” Trump repeatedly paused during the remarks in an apparent effort to allow for a translation, before he was informed midstream: “You need not wait for any translation.” The awkward back and forth was, in part, due to technical difficulties. At one point, Trump said he was having trouble hearing. “The sound system is terrible because there is a huge delay and feedback,” he said.

The $150,000 donation made by Pinchuk, the son-in-law of former president of Ukraine with a questionable record on corruption was the largest donation to the Trump foundation in 2015, other than money Trump contributed, again raising questions about the charitable organization, which during the campaign appeared to be little more than a piggy bank for Trump to collect other people’s money in the name of charity and distribute it in his own name. “Mr. Pinchuk, who has been accused by steel makers in the United States of illegally dumping steel on the American market at artificially low prices, drew more scrutiny during the campaign for his ties to Hillary Clinton and her family foundation,” according to the New York Times. “He has donated more than $13 million to that organization since 2006.”