Investigators are combing through evidence in the wake of New York City’s deadliest mass shooting since 2000, trying to figure out more about the gunman who unleashed an assault-style rifle in Midtown,

Officials said the gunman fatally shot himself after his attack, which set off a chaotic scene that rippled out into the heart of Manhattan during rush hour.

A police officer was among the dead. The gunman carried an M4 rifle and died after shooting himself in the chest, police said.