During the end pursuit, Garzah walks past a plump, dark-haired lady in a floral dress, pushing a baby in a stroller. As Donahue pursues in a following scene, he passes the same woman, now walking without her baby carriage and her left hand bandaged.
In the scene near the end where Garza is running along a street in New York, the car holding the camera (in the passenger window) is visible in the store windows, keeping pace with the actor as he stops and starts.
When the police visit Ed Garzah's (the killer's brother) work site, Ed is shown holding a small hammer (8 or 12 ounce). Considering he is doing rough carpentry, apparently building forms for concrete, he would be using a heavier hammer (16 ounce or more).
Correction of: "In the opening scenes the narrator says "as you see this is an island" it is Midtown & Central Park, not Long Island."
Yes, not Long Island, but still an island. Midtown and Central Park are on the Island of Manhattan. It is surrounded by The Hudson, East and Harlem Rivers.