A federal grand jury in Arizona has subpoenaed records from a review that Republican lawmakers conducted of the 2020 presidential results and that confirmed President Donald Trump lost.

The subpoena opened a new front in the Trump administration’s expanding hunt for evidence that has never surfaced to support the president’s claims of widespread fraud. The law enforcement steps have alarmed election officials and Democrats who fear that the administration is building an argument for interfering in this year’s midterm elections.