Rekia Boyd Lawsuit: Family Of Unarmed Woman Killed By Off-Duty Chicago Cop Sues City (VIDEO)

It was an unseasonably warm March night when 22-year-old Rekia Boyd was gunned down by an off-duty police officer in Chicago's Lawndale neighborhood.

Boyd was with a group of friends around 1 a.m. near 15th Place and Albany Avenue when off-duty Chicago Police Det. Dante Servin pulled up in an unmarked vehicle and told the group to "shut up," according to her family.

What happened next, according to an attorney for Boyd's family, was truly shocking: After a verbal altercation with one person in the group, Servin allegedly opened fire. As the friends ran away, 39-year-old Antonio Cross was shot in his hand and Boyd was shot in the head, according to the attorney, James D. Montgomery. She died nearly 24 hours after the shooting.

"Rekia Boyd was shot and killed on March 21, 2012, without any legal justification," Montgomery said during a Friday press conference. "Her young life was snuffed out by an aggressive, intimidating police officer who provoked the confrontation and when met with a verbal rejoinder took the life of an innocent young woman."

"The police spokesperson publicly claimed that the officer fired in defense of his life when a man approached his vehicle and pointed a gun at him," Montgomery said. "Incidentally, no gun was ever found."

Initially, the police department claimed that Cross approached Servin with a weapon. Allegedly fearing for his life, Servin opened fire. But the Independent Police Review Authority has since stated that no weapon was found on the scene.

In an intense interview with WGN News , Cross said that he was talking on the phone when the officer began shooting into the crowd. Cross asked the station how the officer could have thought his phone was a weapon when he was holding it to his ear and talking.

Montgomery said the shooting happened simply because someone "mouthed off" to the officer.

Darian Boyd, the victim's older brother, told the Huffington Post that Servin lived in the Lawndale area, and had made a comment prior to the incident about wanting some "respect" from the community.

"He basically said, 'What do I have to do to get some peace, quiet and respect ... shoot someone?'" Darian Boyd told The Huffington Post, adding that there is a possibility that Cross exchanged words with the officer but that a weapon was never involved.

Boyd's family is now suing the city of Chicago and the detective in connection with her murder.

Darian Boyd and Martinez Sutton, another brother of the victim, started a website and petition hoping to find justice for their sister. Darian Boyd said that several witnesses believe that Servin was intoxicated when the shooting occurred. He added that his family has been canvassing the neighborhood looking for answers.

Ilana Rosenzweig, the review authority's chief administrator, said in a statement that it has identified several witnesses and also gathered physical evidence from the scene. The authority has passed on its findings to the Cook County State's Attorney's office and that the investigation is ongoing, she added.

"I couldn't believe it," Sutton said during the Friday press conference. "I saw a news story about a 22-year-old woman who had been shot in the head. I was like, I feel sorry for that family. I come to find out, we were the family."

(Watch video from the conference above.)

According to a community news site, Servin is still working on duty with the Chicago Police Department while the investigation into his actions continues.

The police would not comment on his status or the lawsuit against the department.

The Cook County State's Attorney's office did not return calls for comment.

The lawsuit against the city comes one day after 61-year-old Howard Morgan was sentenced to 40 years in prison for allegedly attempting to kill four white Chicago police officers. Morgan, an off-duty detective for the Burlington Northern Santa Fe Railway, was pulled over by Chicago police on Feb. 21, 2005, and shot 28 times. He survived, and his family maintains that police are not telling the truth about what happened that night.

"He never fired his weapon," Morgan's wife Rosalind told CBS. "There was no gun residue on his hand, and he didnt fire his weapon."

"They shot him 21 times in the back parts of his body and seven times in the front, and left him there in a puddle of blood," she added. "He made it then, and God will allow him to make it again."

Joseph Erbentraut contributed to this report.