The police moved in before dawn.

Their target was a first-floor apartment on Chicago’s West Side. Among those inside were two top leaders of the Illinois Black Panther Party — chairman Fred Hampton and Mark Clark.

Officers assigned to Cook County State’s Attorney Edward V. Hanrahan approached the dwelling with a warrant authorizing a search for illegal weapons. Gunfire — police claimed they faced a barrage from inside the apartment — erupted shortly after the raid began at 4:45 a.m.

When the shooting stopped, Hampton, 21, and Clark, 22, were dead. Four other Panthers and two police officers were wounded. Seven Panthers in the residence were charged with attempted murder.

The Dec. 4, 1969, confrontation at 2337 W. Monroe St. ended quickly, but the controversy over what exactly happened — fought over in the pages of the city’s newspapers, on local TV and in the courts — reverberated for years to come.

The fault lines emerged hours after the raid ended.

“The immediate, violent, criminal reaction of the occupants in shooting at announced police officers emphasizes the extreme viciousness of the Black Panther Party,” Hanrahan said in a statement after the shooting.

“The man murdered Fred Hampton,” Bobby L. Rush, then minister of defense for the Illinois Black Panthers and today a Democratic congressman from Chicago, said of Hanrahan in a TV interview. “We’ll prove it to the world that Fred Hampton was murdered.”

With stark divides between rich and poor, a police department notorious for brutality and a history of discrimination against African Americans, Chicago was “certainly emblematic of that era of political, racial and social strife,” said Jane Rhodes, head of the African American Studies Department at the University of Illinois at Chicago and author of a book on the Panthers.

After rioting that followed the April 4, 1968, assassination of Martin Luther King Jr., Chicago Mayor Richard J. Daley ordered police to shoot to kill suspected arsonists. Later that summer, during the Democratic National Convention, police and antiwar protesters clashed in Grant Park in skirmishes broadcast around the world.

The tumult continued into 1969 during the “Days of Rage” that culminated with rock-throwing radicals rampaging through the Loop on Oct. 11. Twenty-three police officers were injured, and more than 100 arrests were made, The Washington Post reported.

Looking back on those days, Rush said in an interview, “Chicago was in an upheaval. Change was very much a part of the atmosphere.”

Hampton, who had been convicted of armed robbery less than a year before the raid, was at the center of the storm and frequently in the headlines. Active in the NAACP as a teenager, he joined the Panthers and brought talent and energy to the task of leading the party in Illinois, Rhodes said.

The party ran a preschool breakfast program and was planning a medical clinic but also displayed “a concentration on and almost an obsession with — firearms and military discipline,” according to a federal grand jury report on the raid. Party leaders, including Hampton, routinely referred to police as “pigs” and vowed to resist police brutality with violence.

The bellicose rhetoric raised the party’s profile and energized organizing efforts, Rhodes said. But it made enemies. The party’s militancy aroused the “ire and animosity” of the Chicago police department, Rush said. In 1969, after a gun battle between police and the Panthers in which two officers were killed, the Chicago Tribune editorialized that the Black Panthers “have declared war on society” and as a result “forfeited the right to considerations ordinary violators of the law might claim.” The headline over the editorial: “No quarter for wild beasts.”

FBI Director J. Edgar Hoover called the Black Panther Party “the greatest threat to the internal security of the country” — and the bureau acted accordingly. A civil suit filed by survivors of the raid would produce evidence that an FBI informant provided a diagram of the apartment to Chicago police. The suit also revealed that Hampton and the Illinois chapter of the party had been targeted by the FBI’s COINTELPRO campaign to disrupt and undermine militant groups.

Those disclosures came long after Hampton and Clark were killed. But in the aftermath of the raid, many were already convinced it was part of a coordinated assault hatched by the FBI and the Nixon administration Justice Department.

“If the United States is successful in its drive to crush the Black Panther Party, it won’t be long before it seeks to crush your party,” the Rev. Ralph David Abernathy of the Southern Christian Leadership Conference said at Hampton’s funeral.

Tensions ran high in the hours after the raid. Rush said he went underground after learning police were looking for him. He stayed at a Catholic church on the South Side and in an apartment attic on Chicago’s Gold Coast before turning himself over to police at a church service presided over by the Rev. Jesse L. Jackson.

“If I was out on the street,” Rush told a Chicago audience Nov. 24, according to the South Side Hyde Park Herald, “they would have shot me down.”

Meanwhile, doubts about the official version of events proliferated.

Because officials failed to seal the scene, the Panthers conducted tours of the apartment to highlight what they said was evidence that police did most of the shooting.

“The hundreds of people who have trooped through represent a broad spectrum” of Chicago’s black community, John Kifner of the New York Times wrote. “There are youths, workmen in paint-stained clothes, middle-aged women in flowery hats, neatly dressed office workers, elderly people and postal workers in gray uniforms. Many give a clenched fist salute when they leave.”

The battle to shape public opinion quickly moved to the front pages of Chicago’s hypercompetitive newspapers.

On Dec. 10, the Chicago Daily News bannered a Page 1 story with the headline “Panther story of killings.” Based on eyewitness accounts provided to the newspaper by defense attorneys for the seven Panthers in the apartment, the story said police “forced their way” into the dwelling after knocking at the door.

“Without warning, the detectives began firing toward mattresses near the southeast corner of the living room of the apartment, the eyewitnesses said. Clark was killed in the volley.” Hampton, according to the eyewitnesses, was apparently shot “while still in his bed.”

The next day, the Tribune published an exclusive of its own based on accounts from police who were made available by Hanrahan “to refute what he termed the orgy of sensationalism in the press and on television.”

Hanrahan told the Tribune that he and his officers had no idea Hampton or Clark were in the apartment. To buttress claims that police were under attack, Hanrahan and his aides released photographs “which they said conclusively proved the Panthers opened the battle by firing a shotgun blast thru the apartment door,” according to the Tribune story.

Police also staged a filmed reenactment of the raid broadcast on WBBM-TV in which officers “crouched as if dodging bullets and held their hands as if carrying shotguns and machine guns,” according to the Chicago Sun-Times.

But the prosecutor’s attempt to manage the news backfired. The day after the Tribune published its story, the Sun-Times published its own Page One scoop. The photos released by Hanrahan’s office did not display bullet holes caused by a Panther fusillade but were simply nail heads, the Sun-Times reported. Daily News columnist Mike Royko wrote that he inspected the apartment “more than once” and concluded Hanrahan’s claim that police encountered gunfire from the Panthers “doesn’t mesh with the condition of the place.”

In the months that followed, Hanrahan began to lose in the courts. On May 8, 1970, attempted-murder charges against the seven Panthers at the apartment were dropped after Hanrahan conceded ballistic tests and forensic issues undermined the state’s ability to prosecute its case. Several weeks later, the federal grand jury issued its findings and concluded that virtually all of the empty shells and bullets recovered at the scene had been fired by police weapons.

“One cannot read the entire report,” The Washington Post editorialized, “without being appalled at the conduct of law enforcement agencies in Chicago.”

The stakes for Hanrahan — and Daley’s vaunted Cook County Democratic machine — escalated dramatically the following year, when the state’s attorney was indicted along with 13 others on charges that they attempted to prevent the prosecution of police officers for their role in the raid.

Cook County Democrats endorsed Hanrahan for reelection in 1972 despite the indictment, only to withdraw their backing after furious reaction from the black community. A defiant Hanrahan told the Tribune “I’m not going to back down for anybody” and stayed in the race.

Hanrahan won the Democratic primary without Daley’s endorsement and was acquitted with his colleagues by a Cook County judge in late October, but controversy over the raid proved too much to overcome. Polls before the election showed his Republican opponent, Bernard F. Carey, drawing up to 75 percent support in Chicago’s black wards, Kifner wrote. On Election Day, voters delivered what Chicago journalist Joel Weisman, writing in The Post, called a “severe jolt” to the Daley organization by electing Carey.

In 1982, the Justice Department, the city and Cook County settled the $47 million civil suit filed by survivors and the families of Clark and Hampton for $1.82 million. A Justice Department attorney said the settlement did not concede wrongdoing, but one of the attorneys for the plaintiffs described it as “an admission of the conspiracy that existed between the FBI and Hanrahan’s men to murder Fred Hampton,” according to the Times.

The repercussions of the raid extended into the 21st century. Hampton’s example inspires young African Americans today fighting “the excesses of the police agencies in our nation,” Rush said. The alliance between the city’s black community and liberal whites forged in the campaign to defeat Hanrahan “created the independent coalition that resulted in the election of Harold Washington as Chicago’s first black mayor” in 1983, Panther attorney Jeffrey Haas said in a 2009 interview with the Monthly Review. “Some argue that Barack Obama is a direct descendant and beneficiary of that legacy,” Haas said.

Although he defeated Obama in a 2000 congressional primary, Rush is among those who see it that way. “Fred Hampton sacrificed his life,” he said, “and with that sacrifice, the politics of the nation, the politics of the African American community and the politics of Chicago changed forever.”

Read more Retropolis: