Thomas Barrack, former chairman of investment firm Colony Capital, is going on trial this week for allegedly acting as an agent of a foreign government without making the proper notification to the U.S. government.

Specifically, Barrack — a supporter of and fundraiser for President Donald Trump — is accused of illegally lobbying U.S. officials to support policies favoring the United Arab Emirates.

Barrack's assistant, Matthew Grimes, was also charged in the case.

“The defendants are alleged to have used their access to the most powerful members of the government — congressmen, senior executive branch officials, and even the president of the United States — to provide information to, and otherwise assist, a foreign government,” federal prosecutor Ryan Harris said in a February court filing in the case, US v. Al Malik Alshahhi.

Barrack and Grimes pleaded not guilty.

Prosecutors say that Barrack pushed for the UAE’s preferred candidates for positions in the Trump administration, as well as providing that country nonpublic information about White House thinking on the UAE and Saudi Arabia’s dispute with Qatar, Bloomberg reports.

The government further alleges that the quid pro quo for Barrack was a $74M investment by Mubadala Investment Co. (which is controlled by the UAE) in a Los Angeles office tower, and a $300M Abu Dhabi Investment Authority in a Colony Capital digital infrastructure fund.

Barrack's defense lawyers say that the Trump administration knew he had contacts among various Middle East leaders, "since at various points these American officials utilized Mr. Barrack as a helpful source of information regarding the Middle East. He was never an agent of the UAE.”

Jury selection in the trial starts Monday in U.S. District Court, Eastern District of New York.

Barrack, who founded Colony Capital in 1991, stepped down last year as executive chairman of the investment firm. Recently, Colony rebranded itself as DigitalBridge Group.