Impeachment investigators have released the transcript of a recent interview with the Office of Management and Budget official who signed the document freezing U.S. aid to Ukraine.

Mark Sandy testified before House lawmakers behind closed doors earlier this month.

The impeachment inquiry into President Donald Trump seeks answers to why the U.S. withheld aid from Ukraine. Government officials have testified the aid was tied to Ukraine’s willingness to announce an investigation into Trump’s domestic political rivals.

In a July 25 phone call Trump asked Ukrainian President Volodymyr Zelensky to investigate former vice president and 2020 presidential candidate Joe Biden. Trump has said he put “no pressure” on Zelensky.

Read Mark Sandy’s full testimony.