A Texas mayor was charged Thursday in an illegal voting scheme.

Richard Molina, the mayor of Edinburg, a city along the U.S.-Mexico border that is home to U.S. Customs and Border Protection operations in the Rio Grande Valley, was arrested and charged with engaging in organized election fraud and two counts of illegal voting, according to the Associated Press.

His wife, Dalia, was charged with one count of illegal voting. Eighteen people total have been arrested in the scheme.

Authorities allege Molina encouraged voters to lie about their addresses. He was elected in 2017, beating Edinburg’s longtime mayor by about 1,200 votes.

City spokeswoman Cary Zayas said Molina “very adamantly” denies wrongdoing.

The Texas attorney general’s office declined to say whether the outcome of the election was affected by the alleged fraud.

It’s unclear what Molina’s party affiliation is. Municipal elections in the state are nonpartisan.

The arrests come amid controversy over efforts by he Texas secretary of state’s office to purge voter rolls, claiming that thousands of registered voters could be noncitizens.