Two top Border Patrol officials are under investigation after they partied with and were hosted by a wealthy Mexican tequila maker who hoped to make a Border Patrol-branded tequila, three sources familiar with the probe told NBC News.

The sources said the relationship between distiller Francisco Javier González and Border Patrol chief Jason Owens and Rio Grande Valley Border Patrol sector chief Gloria Chavez has raised questions about whether the officials disclosed their contact with a foreign national, a requirement for those who receive top security clearances, and whether they accepted anything that could be a violation of ethical rules. The Customs and Border Protection Office of Professional Responsibility, the agency’s internal watchdog, is investigating.

In photos posted on social media this February, Owens and Chavez were seen in Jalisco, Mexico, with González at Tequila Casa de los González, his family’s distillery complex.