Chicagoans Rally For Rekia Boyd, Woman Fatally Shot By Off-Duty Detective (VIDEO)

Some 200 protesters angered by a Chicago police officer's fatal shooting of a 22-year-old woman last week rallied Tuesday outside the officer's home, calling for justice for a woman police admit was an innocent bystander.

Rekia Boyd was fatally shot in the city's Lawndale neighborhood early last Wednesday . The shooting occurred around 1 a.m. near the intersection of 15th Place and Albany Avenue as an off-duty Chicago detective stopped to look into a "disturbance" that reportedly involved a group of people gathering near Douglas Park.

According to police, after the detective stopped and announced his office, a man -- Antonio Cross, 39 -- allegedly advanced toward his car with a gun in hand. The officer opened fire from his car, striking Cross in the hand and Boyd, who was standing nearby, in the head.

Boyd was transported to Mt. Sinai Hospital in critical condition and died Thursday. Cross was charged with misdemeanor aggravated assault as no weapon was recovered from the scene of the incident.

While police maintain that Cross was armed and deemed the shooting justified, family members told NBC Chicago that he was only holding a cell phone . Witnesses told ABC Chicago that no one pulled a gun on the off-duty officer.

Chicago Police admit that Boyd was an innocent bystander in the incident , ABC reports. The officer, who lives on the same block where the shootings took place, did not comment on the incident or protest Tuesday.

"This young beautiful girl dead in the streets. Why? " Martinez Sutton, Boyd's brother told ABC last week. "All we want to know is what happened?"

Cross told ABC Tuesday that, "I want people to know I didn't have no gun. She didn't have no gun. I want people to know that girl was killed for nothing."

Ald. Michael Chandler (24th) spoke out Tuesday against the city's defense of the shooting. He contends that investigators are not doing a thorough job looking into the incident by interviewing neighbors who reportedly overheard the officer tell a crowd "What do I have to do around here to get some peace, quiet and respect? Shoot someone? " the day before Boyd's death.

"A young person's life [has been] taken away and there is not one person that has been out on these streets to canvass the area to talk to any of these witnesses ," Chandler told WBEZ.

The Lawndale shooting that killed Boyd is currently under investigation by the Independent Police Review Authority, which declined to comment on the matter to WBEZ. The incident is just one of a series of police-involved shootings reported in Chicago in recent days .