People might also be afraid that stepping forward means standing up to gangs. While police said Hadiya was not involved with gangs, they say her death was gang related.
"People are afraid if they do (come forward) their family members or they themselves might be shot," said Tio Hardiman, of CeaseFire, a violence prevention group that interacts with Chicago gang members.
Investigators suspect the gunman opened fire on Hadiya and others taking cover from the rain at a park because he may have believed someone in the group was associated with a rival gang.
"It's always legitimate when you are talking about something of this magnitude, where people are shooting each other," McCarthy said. But the superintendent said he's confident the anger over the death of the teenager will win out.