An 18-year-old Chicago woman has been killed on the same day her sister sat on the stage behind US President Barack Obama, listening to him push for gun control legislation.
Janay Mcfarlane was shot once in the head about 11.30pm on Friday in North Chicago, Lake County Coroner Thomas Rudd told the Chicago Sun-Times.
Mcfarlane, the mother of a three-month-old boy, was in Chicago visiting friends and family.
North Chicago police said two people were being questioned in connection with Mcfarlane's death, but no charges had been filed.
"I really feel like somebody cut a part of my heart out," Angela Blakely, Mcfarlane's mother, said. She said the bullet that killed Ms Mcfarlane was meant for a friend.
Hours earlier, Mcfarlane's 14-year-old sister sat near Mr Obama at Hyde Park Career Academy, where he spoke about gun violence and paid tribute to Hadiya Pendleton, the 15-year-old student shot dead last month in a Chicago park.
Police have said it was a case of mistaken identity, and two people have been charged.
Hadiya's death was one of more than 40 homicides in Chicago last month, a total that made it the deadliest January in the city in more than a decade.