The parents of Alex Pretti, a U.S. citizen shot and killed by federal immigration agents in Minnesota in January, criticized U.S. President Donald Trump’s administration on Tuesday for withholding evidence from local prosecutors who are investigating the incident.

“Our experience with the Department of Justice has left us wondering how Alex will ever get justice,” Pretti’s father Michael said at a news conference in Minneapolis, the first time the family has spoken publicly since his death. “Do your job and stop shielding Alex’s killers,” he demanded.

The Justice Department said in a statement?that “communications with family members, if any, come at a later stage of a case, such as indictment, initial appearance, plea, trial?or sentencing. Those communications do not typically occur during an investigation.”