FCC Chairman Brendan Carr sent a letter to Comcast on Tuesday announcing a probe of the company's relations with NBC affiliates.

The letter, dated Tuesday and released publicly Wednesday, was addressed to Comcast CEO Brian Roberts. In it, Carr, who was appointed by President Donald Trump, said he had directed the FCC’s Media Bureau to conduct the inquiry to “ensure compliance with FCC regulations as well as the public interest standard.”

The chairman of the Federal Communications Commission has opened a formal inquiry into Comcast’s NBC Universal over co