So far this month, 42 people have been murdered in Chicago, making it the deadliest January in more than a decade.
Chicago police said Wednesday Pendleton and her friends were, by all accounts, good kids, but they were hanging out in a South Side park that is apparently gang turf. Police say that might be why they came under fire from an offender who is still on the loose.
Pendleton's death has sparked grief, with a father wondering what he could have done differently to protect his daughter.
"She was hanging out. It was a warm day. She was hanging out with her friends. They had finals," said Nathaniel Pendleton.
Classmates of the 15-year-old sophomore are remembering her as a smart, vivacious and likeable young lady.
"She was a sweetheart," said classmate Derielle Pinckney. "She touched so many of us."
Pendleton was on the volleyball team and was a majorette with the school band. Her teammates and bandmates released balloons in her honor.
Pendleton performed last week in Washington, DC, during inaugurations festivities for President Obama.
Wednesday, the White House expressed sorrow about the deadly shooting.
"It's a terrible tragedy anytime a young person is struck down with so much of their life ahead of them, and we see it far too often," said White House Press Secretary Jay Carney. "The president and first lady's thoughts and prayers are with the family of Hadiya Pendleton."
In Chicago, grief turned into outrage, with Mayor Rahm Emanuel fighting back emotion.
"She had dreams, and this gangbanger, this punk, took that away from Cleopatra, they took it away from Hadiya, and in my view they took it away from the City of Chicago," said Emanuel.
Emanuel visited the Pendleton home Wednesday evening to meet with her family and friends for about an hour.
Chicago Police Superintendent Garry McCarthy met Pendleton's family at the scene of the shooting in Harsh Park. Pendleton was with friends there Tuesday after school let out early for finals when police say a teen ran toward the group and fired several shots.
Pendleton was hit in the back.
"We're here today to stand with the community, to ask anybody in the community with information about this incident to please come forward," said McCarthy. "We cannot let the offender get away with this senseless tragedy."
A reward is being offered for information leading to the arrest of Pendleton's killer. That amount is now $11,000.
Another teenage boy who was shot in the leg is recovering from his injuries.