The suspect in cuffs ... the car window shot out ... and Will Smith's wife screaming in pain -- all captured in dramatic a video taken moments after the ex-NFL star was gunned down this weekend.
The footage, shot by a reporter for NOLA.com, captures the tragic scene as emergency responders tend to Racquel Smith ... who can be heard screaming, "My leg has been shot."
At one point, you can hear a witness describe the shooting ... saying Smith threatened to get HIS gun before Cardell Hayes started shooting.
For the record, Hayes' attorney has said his client only fired in self defense.
Cops say they have only recovered 1 gun from the scene.