Republican legislators in California announced Wednesday that they are sending a letter to the U.S. Department of Justice and to the U.S. Attorneys representing California, calling for a potential federal investigation into who is behind the proposed new congressional maps in California and how they were constructed.

Governor has called for a November special election to let voters decide on a new congressional map designed to flip up to five Republican-held seats.

The California Supreme Court on Wednesday rejected an attempt by Republican legislators to delay Democrats from gerrymandering the state’s congressional districts. The justices said the emergency petition, filed earlier this week, “failed to meet their burden of establishing a basis for relief at this time under” the California Constitution.