WASHINGTON (AP) — The former U.S. ambassador to Ukraine was removed from her post after insisting that Rudy Giuliani’s requests to Ukrainian officials for investigations be relayed through official channels, according to a former diplomat who has spoken with her.

The ambassador, Marie Yovanovitch, is scheduled to testify before congressional lawmakers on Friday as part of the House impeachment inquiry into President Donald Trump. Democrats say they expect her to appear despite the White House’s position that no administration officials cooperate with the probe.

Yovanovitch was recalled from Kyiv in May as Giuliani — who is Trump’s personal attorney and has no official role in the U.S. government — pushed Ukrainian officials to investigate baseless corruption allegations against the Bidens.

In a July 25 call, Trump told Ukrainian President Volodymyr Zelenskiy that Yovanovitch was “bad news,” according to a partial transcript released by the White House.

Neither Giuliani nor Trump have specified their objections. But a former diplomat, recalling a recent conversation with Yovanovich, said she was removed after insisting that a request for Ukrainian officials to join in an investigation be relayed according to long-established protocol.