President Trump filed an election lawsuit in New Mexico, yet another legal challenge to President-elect Joe Biden’s victory more than a month after the contest.

The lawsuit, filed in U.S. District Court in New Mexico by Trump and his legal team on Monday, alleges New Mexico Secretary of State Maggie Toulouse Oliver violated the state’s election code by letting voters deposit absentee ballots in drop boxes at voting locations rather than giving them to the location’s presiding judge in person, according to a statement from the Republican Party of New Mexico.