In the weeks following the partial collapse in October of the Hard Rock Hotel in New Orleans — a disaster that left three people dead and dozens injured — federal investigators conducted three interviews with Delmer Joel Ramirez Palma, a worker who had registered his safety concerns repeatedly before the calamity. They had no trouble finding him; immigration officials detained Palma, an undocumented immigrant, two days after the collapse.

Despite his obvious relevance to the investigations, he was deported late last month. Thus has the judgment of Immigration and Customs Enforcement agents been clouded by the administration’s appetite for enforcement.

Palma, a 38-year-old metal worker, had lived nearly two decades in the U.S., where he was married and had a 10-year-old son, who is a U.S. citizen. He is now back in his native Honduras, where it may be more difficult to draw on his knowledge of the problems that contributed to the collapse.

It’s unclear whether the U.S. Labor Department, under whose auspices the Occupational Safety and Health Administration is investigating the collapse, asked ICE to hold off on deporting Palma. (Under a standing agreement, ICE will hold off on deporting workers who have complained about unsafe work conditions under investigation by the Labor Department.) However, the top official at the Louisiana Workforce Commission, which investigates workplace safety issues, had written to ICE specifically asking that Palma not be deported, saying he was a “crucial witness” in the state’s inquiry.

Palma’s status as a material witness to what may turn into a criminal investigation stems from complaints he raised about construction quality issues. Before the collapse, his concerns were dismissed by supervisors, according to his lawyers. Following it, he joined a lawsuit accusing the project’s developers and construction firm of using substandard materials and other problems.

Unauthorized immigrants, who constitute 15% of the country’s construction workers — and perhaps more in New Orleans — are uniquely vulnerable to exploitation and abuse. Frequently, they have no recourse, and no standing to push back. ICE had ample reason not to deport Palma. By ignoring those concerns, it may have impeded the search for truth in a deadly incident.