Minutes after a federal agent shot and killed a Mexican immigrant in a Chicago suburb last September, a group of police officers stood on the sidewalk trying to figure out the answer to a question of protocol: Who would investigate the shooting?

“Wouldn’t it be state’s, at a minimum?” one Franklin Park officer asked, according to body camera footage.

Chief Mike Witz shook his head. “No, because it’s a federal shooting,” he said. “You’re not going to investigate a federal officer.”

His officers didn’t investigate. In their report, they didn’t even note the names of the two Immigration and Customs Enforcement agents at the scene of Silverio Villegas González’s death. Instead, they deferred to the FBI.

Local law enforcement officials also did not investigate when a Border Patrol agent shot and wounded a U.S. citizen in her car in Chicago less than a month later. Or when an ICE agent in Phoenix shot a Honduran man during a traffic stop later that month.

In fact, local police did not open investigations into six of the 12 shootings by on-duty federal agents that have led to the deaths or injuries of citizens and immigrants since September, a ProPublica analysis found. In three other shooting cases, state or local police said they have opened inquiries, which they called a routine practice in those jurisdictions. And in Minnesota, where ICE and Border Patrol shot and killed two U.S. citizens and injured a Venezuelan man last month, state police have tried to conduct independent investigations only to be thwarted by the Trump administration, which has gone so far as to block officers from a scene, even when they had a judicial warrant.