when she's at home, she's in her bedroom, which has become a shine to alliyah. >> this is my alliyah.his is what i have of her. >> reporter: the walls, pink and purple, alliyah's favorite colors. and pictures everywhere. >> once thing that i really wanted to show you, and everybody out there in the world, is that this is my baby. 6 years old. loved cool, loved life. amazing little girl. this -- this is what they took away from me, and this is what, unfortunately, i am forced to see now. we need to do something. we need to stop this. we need to show these kids that there's options out there, you know? that there's other options besides joining the gangs. there's other -- you have a family, a real family that loves, that wants the best for you, that wants a future for you. >> reporter: for "nightline" unt, i'm alex perez in chicago. >> heartbreaking. our thanks to alex perez for bringing us that story. >>> tomorrow night on "world news" and a special edition of "nightline," we're going to show you what happened when we brought together members of rival gangs for an unprecedented summit.