(NewsNation) — The mayor of a small town located in the Rio Grande Valley of Texas along the Mexico border has been arrested on federal drug trafficking charges, according to court documents obtained by NewsNation.

Progreso Mayor Gerardo Alanis, his brother, and two other defendants were listed in an indictment for allegedly conspiring to distribute cocaine. The charges date back to 2020.

According to NewsNation affiliate KVEO, the investigation started when Border Patrol arrested a former Progreso Independent School District bus driver with about 30 pounds of cocaine. The bus driver pleaded guilty and cooperated with the government, KVEO reported.

The incident triggered a federal investigation, resulting in the arrest of the mayor’s brother Francisco “Frank” Alanis last October. He pleaded not guilty. He could face a minimum of 10 years in federal prison if convicted. Court records indicate he was not allowed to communicate with his brother as a condition of his bond.

Frank Alanis is a former assistant city manager and former president of the school board, according to the district’s website. He is still listed as a school trustee.

Agents returned to Progreso on Monday, when they arrested Mayor Alanis, according to KVEO. He faces one count of conspiracy to possess more than 5 kilograms of cocaine with intent to distribute and two counts of possession of more than 5 kilograms of cocaine with intent to distribute. If convicted, he faces 10 years to life in federal prison.

NewsNation is working to obtain a response from the mayor, but it’s currently unclear who his attorney is.

According to his LinkedIn profile, Gerardo Alanis has been mayor since 2017.

Homeland Security Investigations, the agency leading the investigation, declined to provide NewsNation with more information citing an ongoing investigation.