Six people were killed and two others wounded when a gunman went on a hours-long rampage in Kalamazoo, Michigan, Saturday night, driving around the city and opening fire on unsuspecting victims at an apartment complex, a car dealership and a Cracker Barrel restaurant, NBC News reported.

The suspected killer, a 45-year-old Uber driver named Jason Brian Dalton, was in custody Sunday but had not been charged, police said.

Uber's chief security officer, Joe Sullivan, said Dalton had passed a background check to become a driver. The company was "horrified and heartbroken" and had offered to help investigators, he said.

A 14-year-old girl, who had earlier been pronounced brain dead, squeezed her mother's hand as doctors were preparing to harvest her organs, police said. Amid the carnage, her case stood out as a miracle, authorities said.

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