Investigators said the suspect walked up behind the victim and shot him in the back of the head. The suspect then jumped into a waiting vehicle and sped away.
The shooting happened right across from the Engine 23 firehouse just before 2:00 p.m.
The victim, a 31-year-old man, was taken from the scene in critical condition after firefighters performed CPR. He was pronounced dead at nearby St. Luke's Roosevelt Hospital.
Authorities said the suspect, a man, was wearing a brown hoodie sweatshirt. He fled in a grey vehicle, possibly a Lincoln MKZ.
The motive is not immediately known.
