The FBI will no longer participate in investigations into cases involving alleged assaults on immigration agents, according to multiple sources familiar with the matter.

The federal law enforcement agency would instead be deferring such investigations to Homeland Security Investigations, the sources said. The FBI field offices were informed of the change on Thursday, according to the sources.  

HSI is an arm of Immigration and Customs Enforcement, both of which are overseen by the Department of Homeland Security, meaning the immigration enforcement agency would effectively be investigating incidents involving its own agents. 

The change was first reported by The New York Times. The FBI and ICE did not immediately respond to CBS News’ requests for comment.

The shift comes after fatal shootings by federal immigration officers in Texas and Maine earlier this month.

On July 7, an Immigration and Customs Enforcement officer shot and killed a Mexican national in Houston who had lived in the U.S. for decades. Days later, an ICE officer shot and killed a Colombian man in Biddeford, Maine.

The FBI earlier this year surged resources in Minnesota to investigate alleged assaults on immigration officers who were carrying out enforcement operations in Minneapolis. Some of those cases were later dismissed after prosecutors reviewed the evidence. The issue became a flash point after a fatal encounter between an ICE officer and Renee Good. The Justice Department pressured the FBI and prosecutors to treat the investigation as an assault on a federal officer as opposed to a civil rights investigation into her killing, prompting several prosecutors and an FBI agent to resign.

When HSI was tasked with leading the federal investigation into the fatal shooting of Alex Pretti in Minneapolis in January, with the help of the FBI, the decision raised questions among current and former federal law enforcement officials. 

After concerns were raised, the FBI and the Civil Rights Division were ordered to take the lead on the probe. That investigation remains ongoing.

HSI is not typically tasked with investigating officer-involved shootings and is not structured or equipped to handle core elements of such cases, including ballistics analysis, forensic processing, firearm examinations, video review and large-scale witness canvassing.