A Chicago police officer who fired more than two dozen rounds from an assault-style rifle during a suspicious police shooting in 2011 will keep his job thanks to failures in the city’s police accountability system.

Physical evidence disproves the story officers told about the day they shot and killed 19-year-old Calvin Cross, but city agencies took too long investigating and firing the officers is no longer possible.

Instead, Chicago’s Civilian Office of Police Accountability, which investigates police shootings, recommended a 30-day suspension for Officer Macario Chavez for violating department policy when he chased after Cross, firing round after round from his assault-style rifle. Two other involved officers escaped discipline altogether

In it’s recently released report summing up the investigation the agency said it “would have recommended Officer [Chavez] be separated from the Chicago Police Department based on his actions during this incident. However, COPA, is unable to make such a recommendation because of Illinois State Law,” the report reads.

State law dictates that a 30-day suspension is the maximum available punishment for officers if the incident is more than five years old.

Cross was killed in May of 2011 while walking with a friend in the West Pullman neighborhood of Chicago. Officers said they were forced to fire after Cross turned and shot at them multiple times, however witnesses said Cross did not have a gun. Police did recover one gun on the scene, but it was not found near Cross’ body, and the state police crime lab determined that the recovered gun was inoperable and had not been fired.

Beyond that, investigators did not find any fingerprints on the gun or any gunshot residue on Cross’ hands.

What investigators did find was shell casings showing the three officers fired more than 35 shots while they chased Cross through a residential area in the West Pullman neighborhood.

Cross was killed by a gunshot wound to the face. About a month after his death, Cross’ girlfriend gave birth to a baby boy, a son Cross would never meet.

All of the physical evidence was known to the city in 2013, when the Independent Police Review Authority determined that the officers acted within policy. The case was reopened in 2016 after the city of Chicago paid out $2 million to Cross’ family, and now the city is admitting they got it wrong.

Investigators with the Civilian Office of Police Accountability say the delay prompted by the initial findings prevented them from recommending appropriate discipline for Officer Chavez.

In its report, COPA lists four pieces of evidence indicating that Cross did not have a gun the night he was killed, including testimony from officers and witnesses and the fact that “there is no forensic evidence connecting [Cross] to the revolver” found on the scene. However, the agency decided there was “insufficient evidence” to determine if Cross had the inoperable gun when he was confronted by police.

For that reason, the agency was unable to conclude if the initial shots fired at Cross were within department policy and did not recommend any discipline for Officer Matilde Ocampo. A third involved officer, Mohammed Ali is on medical leave from the department and refused to be interviewed, so COPA did not determine whether Ali violated department policy.

In recommending discipline for Chavez the agency found, “a reasonable officer would have accounted for the significant risk firing multiple shots from a high-powered firearm poses to residents, pedestrians, and occupants of vehicles, especially when firing at a moving target at night while running.”

“A reasonable officer with police training would also have accounted for the fact that alleged firearm was no longer visible, and that cover was available to protect himself,” the agency found.

Investigators also found that Chavez violated policy with his final six shots at Cross, calling them “objectively unreasonable” because Cross had already been shot down and was “not moving.”

Patrick Smith is a reporter on WBEZ’s Criminal Justice Desk. Follow him @pksmid. Email him at psmith@wbez.org.