The U.S. Senate on Monday launched an investigation into the PGA Tour’s merger with the LIV Golf Tour.

U.S. Sen. Richard Blumenthal (D-CT) wrote a letter to PGA Tour Commissioner wondering about the sudden nature of the partnership with the Saudi Public Investment Fund (PIF).

“While few details about the agreement are known, PIF’s role as an arm of the Saudi government and PGA Tour’s sudden and drastic reversal of position concerning LIV Golf raise serious questions regarding the reasons for and terms behind the announced agreement,” Blumenthal said in the letter.

“Accordingly, I write to request documents and information related to the agreement between PGA Tour and PIF.”

The LIV and PIF are controlled by Saudi Crown Prince Mohammad bin Salman.

The PGA Tour and LIV were involved in litigation when the merger was announced last week, as previously reported by The Dallas Express.