Federal authorities have opted out of prosecuting Jason Van Dyke, the former Chicago cop behind the fatal shooting of 17-year-old Laquan McDonald. The decision was made after speaking with the McDonald family, who were reportedly “in agreement not to pursue a second prosecution,” the U.S. Attorney’s Office explained in a news release. The teen’s relatives have denied speaking to anyone about the matter.

Van Dyke was one of few officers to respond to reports of car break-ins in 2014. Upon his arrival, he shot at McDonald, who’d been brandishing a knife in hand. Authorities initially believed the gunfire was justified, but dashcam footage later showed that the teen hadn’t posed a threat. Instead, he was captured walking away from Van Dyke at the time the shooting took place.

Van Dyke was charged with first-degree murder, becoming the first Chicago police officer to get a murder charge for an on-duty shooting in half a century. He was found guilty of second-degree murder and aggravated battery, additionally receiving an 81-month sentence. He was freed from state prison in February on good behavior, which prompted demands from activists, who called for prosecutors to charge him on the federal level. The attorney’s office admitted, however, that the process of prosecuting him in federal court would have been far more difficult than it was in state courts.

“Federal prosecutors would have to prove not only that Mr. Van Dyke acted with the deliberate and specific intent to do something the law forbids, but also that his actions were not the result of a mistake, fear, negligence, or bad judgment,” the office wrote, per CNN. “It requires federal prosecutors to prove beyond a reasonable doubt what Mr. Van Dyke was thinking when he used deadly force and that he knew such force was excessive.”

The office continued, adding that the judge would then have to consider the time Van Dyke spent in prison, factors surrounding his early release and his future as a police officer if he were to be convicted. “Given these factors, there is a significant prospect that a second prosecution would diminish the important results already achieved,” the U.S. Attorney’s Office said.