A former Milwaukee police officer will not be charged with a crime for the shooting death of a 31-year-old man with a history of mental illness that has spurred protests, the Milwaukee County District Attorney’s Office announced Monday.

The April 30 shooting of Dontre Hamilton in a downtown park by Officer Christopher Manney inspired a series of protests in Milwaukee, including one over the weekend that led to dozens of activists being arrested after shutting down I-43.

Manney shot Hamilton 14 times during an incident that occurred after workers at a nearby Starbucks called police to complain about him sleeping in Milwaukee’s Red Arrow Park.

“This was a tragic incident for the Hamilton family and for the community,” District Attorney John Chisholm said in a statement. “But, based on all the evidence and analysis presented in this report, I come to the conclusion that Officer Manney’s use of force in this incident was justified self-defense and that defense cannot be reasonably overcome to establish a basis to charge Officer Manney with a crime.”

The decision comes weeks after prosecutors in Missouri and New York cleared officers in high-profile cases in which police used force in Ferguson, Mo., and Staten Island that have spurred nationwide protests and anger over treatment of African Americans by law enforcement.

The debate over police and relations with the African-American community escalated after the killing of two New York City police officers on Saturday by a man who cited his anger about the Michael Brown and Eric Garner cases on social media.

The Hamilton family released a statement through their attorney saying they were “extremely disappointed” with the decision and that the case “cries out for justice, criminal charges against Christopher Manney, and accountability to Dontre Hamilton’s family,” according to the Associated Press.

Manney showed up to Arrow Park after receiving a voice mail from his acting desk sergeant about “a homeless guy sleeping” in the park and asked him to respond, according to a report from Chisholm’s office.

At the time of the call, Manney was handling another unrelated incident and two other officers were dispatched to the park, but Manney was unaware of it. The two other officers checked on Hamilton twice and determined he wasn’t doing anything wrong.

When Manney arrived in the park after the other officers had left, he said, he found Hamilton laying on the ground in the park and asked him to stand up. He said that Hamilton then stood up and turned his back to him. The police officer began patting-down Hamilton.

As Manney was conducting the frisk, he told investigators, Hamilton twisted his body so he was facing Manney.

Manney, who says Hamilton’s right hand was balled in a fist, said he tried to disengage from Hamilton, according to the DA’s report.

Hamilton lunged and then tried to strike Manney with his fist, according to the police officer’s account. Manny blocked the punch and struck Hamilton with an open palm to the chin. Hamilton then grabbed Manney in the shoulder area, pulling the police officer towards him and struck him on the right side of his head, the report said.

At that point, Manney felt he was losing control of the situation and decided to use his wooden baton on Hamilton.

“Manney separated from Hamilton, removed his baton with his left hand and transferred it to his right hand,” the report said. “When Hamilton continued to be aggressive, Manney struck him once in the rib area with the baton. Manney states that Hamilton trapped his baton between his arms and his torso and spun away from Manney. Manney attempted to retain control of his baton but could not.”

Manney also told investigators that he attempted to hit the emergency button on his radio but couldn’t reach it because of the struggle. As he tried to push away from Hamilton, Manney said, he felt a blow from his baton on the right side of his neck.

He told investigators that he felt he was out of options and decided to draw his weapon in the hope that Hamilton would stop. But he said Hamilton continued to approach wielding the baton.

“Manney fired his weapon but it did not seem to have any effect on Hamilton, so he continued to fire while walking backwards from Hamilton,” according to Manney’s account to investigators. “Hamilton fell forward and Manney continued to fire because he perceived Hamilton still to be a threat. He stopped firing when Hamilton was completely on the ground.”

Chisholm said that a review of the incident by an outside expert on use of force by police, Emanuel Kapelsohn, concluded that Manney’s decision to fire his weapon was in line with his training.

“The Dontre Hamilton incident is quite unusual in that P.O. Manney appears to have tried every level of force on the Force Option Continuum before resorting to deadly force,” Kapelsohn wrote in his report.

Police Chief Edward Flynn fired Manney in October, stating that the officer had identified Hamilton as mentally ill, but ignored department policy and treated him as a criminal by frisking him.

The Milwaukee Police Association condemned Manney’s firing as politically motivated, and members voted no confidence in Flynn soon after the firing.

Manney is currently appealing his dismissal.

Gov. Scott Walker has put Wisconsin National Guard troops on standby in case there is unrest in Milwaukee.

Contributing: Associated Press