(CNN) Democratic Sen. Chris Coons is calling for a hearing into possible presidential interference with US attorneys' offices after reports last month that President Donald Trump personally interviewed candidates for positions with oversight in districts sensitive to his business dealings.

In a letter dated last week, Coons wrote to Senate Judiciary Chairman Chuck Grassley requesting the hearing "based on a series of events that leave me concerned that President Trump does not respect the important boundaries between politics and the prosecutorial decisions of US Attorneys within the Department of Justice."

CNN reported in October that Trump had met with at least three candidates for US attorney positions in New York and Washington, DC, cities that host many of the President's private companies and where investigations into the administration, including the potential collusion between the Trump campaign and Russia in the 2016 election, could play out.

Coons in the letter also cites concern over the resignation of former US Attorney and Acting Assistant Attorney General Dana Boente, who left office late last month.

Coons questions the "sudden nature" of the resignation, and a reported connection between the US attorney's office for the eastern district of Virginia, which Boente oversaw, and the FBI's Russian election interference investigation. Coons writes that a request for additional information on the resignation sent to the Justice Department had not yet elicited a response.

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