Federal authorities arrested 50 people for violating immigration laws in Detroit Saturday as part of an investigation into an alleged cockfighting and illegal gambling ring.

U.S. Immigration and Customs Enforcement spokesman Khaalid Walls told the Detroit Free Press that 86 people were found inside an abandoned building. He added that those arrested will be held in ICE custody “pending removal proceedings.”

Walls said the building was raided in part of an investigation that had been going on for several months, the paper reported. Officials said they found more than 100 birds in the building.

Nearly 140 federal, state and local law enforcement officials were involved in the raid, which was led by Homeland Security Investigations. The Free Press reported that the U.S. Border Patrol, U.S. Agriculture Department and Detroit police assisted.

One person was arrest on a criminal charge. The details of the arrests were not immediately available.

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