More than two dozen people have died in violent clashes with U.S. Customs and Border Protection since 2010. Despite public outrage over some of the killings, no agent or officer has faced criminal charges – or public reprimand – to date.

Yet at least a quarter of the 28 deaths were “highly suspect,” said James F. Tomsheck, the agency’s recently removed head of internal affairs. In a sweeping and unauthorized interview with The Center for Investigative Reporting, he said the deaths raised serious questions about whether the use of lethal force was appropriate.

Instead, Tomsheck said, Border Patrol officials have consistently tried to change or distort facts to make fatal shootings by agents appear to be “a good shoot” and cover up any wrongdoing.

“In nearly every instance, there was an effort by Border Patrol leadership to make a case to justify the shooting versus doing a genuine, appropriate review of the information and the facts at hand,” he said.

Those comments and others represent the most scathing public criticism ever lodged against Customs and Border Protection from a high-ranking official at the nation’s largest law enforcement agency. Although Tomsheck was removed from the internal affairs office, he is assigned to the Border Patrol as its executive director for national programs.