A 15-year-old marching band member who took part in Barack Obama's inaugural celebrations has been shot dead in Chicago.
Police said Hadiya Pendleton was shot in the back on Tuesday in a South Side park. She was taken to hospital, where she died.
The student was one of a dozen teens taking shelter under a canopy during heavy rain when a man jumped over a fence, ran towards the group and started shooting.
He reportedly fled the scene in a car, and no arrests have been made.
The park is just a mile from the president's Chicago home.
Police do not believe Hadiya was the intended target of the shooting. An unnamed teenage boy was also shot in the leg.
Chicago Police Superintendent Gary McCarthy said the gunman may be a member of a gang that considers the park its territory, and that he mistakenly thought one of the teens was from a rival gang.
Hadiya was a member of the King College Prep High School marching band, which performed at several inaugural events in Washington DC.
On Wednesday Hadiya's father, Nathaniel Pendleton, spoke at a police news conference held in the park where his daughter was shot.
"He took the light of my life," Mr Pendleton said.
Speaking directly to the suspect, he added: "Look at yourself, just know that you took a bright person, an innocent person, a non-violent person."
Damon Stewart, Hadiya's godfather, said she was a good student who wanted to become a doctor or a lawyer, and who had looked forward to her trip to Washington.
"She was a very active kid, doing dance, cheerleading, who felt like she could accomplish just about anything," he said.
White House Spokesman Jay Carney relayed the Obama family's condolences.
"As the President has said, we will never be able to eradicate every act of evil in this country, but if we can save any one child's life, we have an obligation to try when it comes to the scourge of gun violence," he said.
The number of murders in Chicago surged above 500 in 2012. There have already been 42 killings in the city this month - more than in any January in over a decade.