The American Civil Liberties Union is seeking a federal investigation into whether Border Patrol checkpoints in southern Arizona violate constitutional rights.

According to the Associated Press, the union wants an investigation into allegations of constitutional abuses by Border Patrol agents at checkpoints in Arizona.

The ACLU reports that a formal complaint has been filed with the Department of Human Services describing abusive and unlawful behavior by U.S. Border Patrol officials.

The Arizona-Sonora border is among the nation’s busiest with many Border Patrol checkpoints, especially along 1-19, which is a major route to and from Mexico. While some checkpoints such as Nogales can be congested, checkpoints are typically not supposed to take long to pass through, if proper documentation is presented.

But in a complaint sent to the Department of Homeland Security’s Office of Inspector General on Wednesday, the union points to 12 cases in which U.S. citizens' say their rights were violated.

The ACLU accuses agents of conducting illegal searches and prolonged detentions, outside the agency's mandate of immigration enforcement.

While the ACLU believes that the Border Control abuses its power at these checkpoints, the National Border Patrol Council disagreed with the allegations and said that agents may stop any drivers based on suspicions that they are committing a crime.