A senior federal prosecutor in Washington resigned on Tuesday, citing what she called an improper demand by appointees of President Donald Trump’s administration to launch a criminal probe of a government contract awarded under former President Joe Biden.

Denise Cheung, who supervised criminal cases at the U.S. Attorney’s Office in Washington, said she had been ordered to open a probe into a contract that she did not identify and that she believed the request was not supported by evidence, in a letter reviewed by Reuters.

When she declined to launch a grand jury investigation citing a lack of evidence, she said she was ordered instead to pursue an asset seizure to prevent the recipient of the contract from drawing down the government funds.