A police officer in Austin, Texas, learned this week that he will not be prosecuted for killing an unarmed black man in 2013 after a judge affirmed his immunity as a deputized federal agent and threw out the charge against him. Charles Kleinert, who killed Larry Jackson Jr. in July 2013 while serving as a city police officer and also a member of an FBI task force, faced a manslaughter trial until a federal judge ruled Thursday that he had protection from state charges.

Judge Lee Yeakel of the U.S. District Court for the Western District of Texas said Kleinert, 51, was shielded by the supremacy clause of the U.S. Constitution, which holds that federal agents are not criminally liable for deaths that occur in the course of their duties, the Guardian reported. Kleinert shot Jackson in the neck during a struggle at the end of a pursuit, and was indicted for manslaughter by a grand jury last year.

The Austin officer said he fired his pistol by accident and intended only to strike Jackson, whom he was pursuing over suspected bank fraud. Adam Loewy, a lawyer for Jackson’s family, called Yeakel’s decision a “complete outrage” and planned to ask the U.S. Department of Justice to step in.

“This is a legal technicality that will allow a killer to walk free,” Loewy said Thursday, according to the Guardian. “It is one of the most horrendous moments in the history of civil rights in this country.”

Kleinert’s attorneys successfully argued that despite being employed by the Austin Police Department he was carrying out his duties as a federal officer when he killed Jackson. Prosecutors countered that in his pursuit of Jackson Kleinert flagged down a car and yelled, “Austin police – stop!” and flashed his Austin police badge to the driver (not Jackson). But the judge, rightly, did not buy it, said Eric Nichols, an attorney for Kleinert.

The prosecution should never have brought the case, Nichols said. Texas prosecutors tried to “second-guess, Monday morning quarterback or micromanage the conduct of a federal officer,” he added.