Officers are hoping to break the code of silence and find a second suspect in the shooting death of 8-year old Tanaja Stokes.
Police made one arrest in the case on Friday.
On Sunday, one day after the 7-year-old who survived the shooting was released from the hospital, officers were back in her neighborhood passing out fliers and interviewing potential witnesses.
The two girls were jumping rope near the intersection of 107th and Indiana in the Roseland community Tuesday when shots were fired in their direction.
Officers gave an update on the case Sunday afternoon at Area Two Police Headquarters.
The family of the victims say they are tired of the gang violence and the crime and senseless killings taking over their neighborhoods. They say that living on the streets of Chicago is like living in a war zone.
"There's one more person out there to be brought to justice as well, so once again, I am begging you, turn yourself in to the police," said Chicago Police Commander Keith Calloway.
Detectives and community activists are asking for the community's assistance in making a second arrest.
"This is another way of the code of silence being broken on the street," said CAPS Implementation Office Director Ron Holt. "It has been done in the past - it proved itself out."
Steshawn Brisco, 18, was charged Friday with murder and aggravated battery and held without bond on Saturday. The courts said he had bragged that he and another person carelessly let loose shooting in the direction of 107th Street.
"He didn't care who was there, and he didn't care who was killed," said Calloway. "If you know where he is hiding... call the Area Two detectives."
Brisco's mother says her son is currently on probation for another crime and has been in and out of juvenile detention a number of times.
Alice Thomas, the mother of the victim who was shot in the head and treated, said police know who they are looking for, and that she is looking for justice.
"I just hope they catch them because they were senseless about what they did," said Thomas. "They didn't care, and they still don't care."
Activists say that in addition to the code of silence among criminals there is a silence and fear that permeates certain neighborhoods.
They say the silence needs to be broken, and people need to help police fight the crime in their neighborhoods.