Five men from India were arrested in Nogales, Sonora on Saturday after they were allegedly caught with altered immigration documents while headed toward the U.S. border.

According to media reports, the men, whose ages range from 18 to 34, were nabbed on the Carretera Internacional after a municipal police officer stopped the taxi they were traveling in for speeding and disobeying traffic signals.

The officer tried speaking with the men, but grew suspicious when they didn’t understand Spanish, the newspaper Nuevo Dia reported. When the driver and passengers were taken to the police station, an inspection of the Indians’ documents turned up several irregularities, the paper reported.

The case was subsequently turned over to a federal prosecutor.

In March, police in the border city reportedly detained six men from India who were reportedly waiting to cross illegally into the United States, and then arrested two people who were allegedly conspiring to help them do it.