In a letter sent Wednesday, Johnson and Grassley requested the State Department provide additional information about how the Obama administration took steps to “ensure that policy decisions relating to Ukraine and Burisma were not improperly influenced by the employment and financial interests of family members.”

In addition to records related to Hunter Biden, Johnson, the Senate Homeland Security Committee Chairman, and Grassley, the Senate Finance Committee Chairman, asked for information related to his business partners Devon Archer and Christopher Heinz. Hunter Biden co-founded Rosemont Seneca Partners with Heinz, the stepson of former Secretary of State John Kerry, and Archer, who attended Yale with Heinz.

The letter cites information newly released by the State Department under the Freedom of Information Act, and first reported by John Solomon, a contributor to Fox News.

The release includes an internal State Department email detailing efforts by Karen Tramontano, chief executive of the consulting firm Blue Star Strategies, to meet with undersecretary of State Catherine Novelli in February 2016. Tramontano, whose firm worked for Burisma, wanted to raise concerns about remarks made by Geoffrey Pyatt, then the U.S. ambassador to Ukraine, condemning Burisma for corruption, according to the email, which states that Tramontano cited Burisma’s ties to Hunter Biden. Grassley and Johnson requested additional information about the meeting.

The release also includes emails referring to a 2015 meeting between Hunter Biden and Antony Blinken, a longtime Joe Biden aide who was then serving as deputy secretary of state, and a March 2, 2016, meeting between Kerry and Archer. Archer served on Burisma’s board alongside Hunter Biden.

Biden successfully pressured Ukraine to fire its prosecutor general in March 2016. At the time, the prosecutor, Viktor Shokin, had open investigations into Burisma and its owner. Biden’s supporters have pointed out that other Western officials viewed Shokin as corrupt and wanted him removed. They have also argued that Shokin’s investigations into Burisma had been long dormant at the time of his firing.

In Thursday’s letter, the senators asked whether the State Department’s inspector general had reviewed potential conflicts of interest related to Hunter Biden’s work for Burisma while the vice president was working on Ukraine-related issues.

They requested that the information be provided by November 20.

