Former Secretary of State Rex Tillerson testified Monday against Donald Trump inaugural committee chair and long-time Trump ally Tom Barrack, saying that Barrack would have frequent meetings with Trump to get information from him and to urge Trump to take positions favorable to his benefactor, the United Arab Emirites, ABC News reports.

Barrack is charged with a number of offenses, including acting as an unregistered foreign agent, conspiracy, obstruction of justice and making false statements to federal investigators.  Prosecutors allege Barrack would use his access to Trump to lobby for UAE interests, using two men–Matthew Grimes, 27, an Aspen, Colorado-based former executive at Barrack’s company, and Rashid al Malik, 43, an Emirati national–to get messages from the UAE’s government.  Both men are facing charges, but Malik fled to the UAE before being detained.

While Barrack served as Trump’s inaugural chair and as an unofficial Trump advisor, he was seeking an investment from the UAE valued at hundreds of millions of dollars.  Barrack failed to reveal his connection to the Emiratis in various disclosures, including when he was being interviewed by the FBI.

Tillerson said that Trump and Barrack would discuss situations involving the Emiratis, who were having a standoff with US-alligned Qatar at the beginning of the Trump administration.  US policy had been to stay out of the issue even as Arab nations set up a blockade of Qatar, but Barrack was lobbying for US intervention on behalf of the Emiratis.

On the stand, Tillerson stated that by possibly getting information from Trump that the US had on the UAE-Qatar situation, Barrack could shape how Trump directed US policy.  “You really don’t want outside parties to have access to that information and use it to their advantage,” he testified.