Hadiya Pendleton's 'twin' describes death of best friend

Weekend sleepovers, a love for reading and a similar goofiness kept the girls close, she said.

"Our freshman algebra teacher couldn't tell us apart, so he just joked and called us each 'twin,'" the friend said. "We always pretended to be sisters."

Police announced that the reward for the arrest and conviction for Hadiya's killer has been raised to $24,000. The money was raised by clergy and other community leaders. Superintendent Garry McCarthy said a lot of tips have been pouring in.

Police have described the gunman as an African-American male 18 or 19, 5-foot-6 to 5-foot-7, 140 to 150 pounds with a dark complexion. He was wearing a blue skullcap, a gray hooded sweatshirt and beige pants.

Police have stressed that the teens in Hadiya's group who had gathered in the park were not involved in gangs, but that they believe the gunman may have mistaken them for rival gang members.

While there haven't been any gang problems at the park, there has been an internal gang conflict brewing nearby among the Gangster Disciples, police said.

In addition to Hadiya's homicide, there have been two shootings about half a mile from Harsh Park in the first month of 2013, according to police records.

As emergency responders raced to the park Tuesday, the nurse kept pressure on the 17-year-old's leg while Hadiya's best friend felt for Hadiya's pulse.

She had lifted her friend's sweater and saw that she was shot in the back. Blood was everywhere.

Hadiya was mouthing words, seemingly trying to speak.

"She held my hand tighter and I was like, 'We love you, we love you, we love you,'" she said.

Tribune reporters Jeremy Gorner and Cynthia Dizikes contributed.