Nowak was handcuffed by police as he lay dying at the scene after Digwa lied, claiming he had been racially abused by the teen and had acted in self-defence.
He told officers his turban had been knocked off and that he had been injured.
Bodycam footage released by Hampshire and Isle of Wight Constabulary, with the family’s permission, showed officers arriving at the scene and speaking to Digwa and others.
Nowak, who is seen on the ground in the video, can be heard saying “I’ve been stabbed” and “I can’t breathe” multiple times.
The footage shows officers turning Nowak onto his side and handcuffing his hands behind his back, and after a couple of minutes he becomes unresponsive.
An officer proceeds to tell him he is under arrest for assault.
Two police officers are being investigated for potential gross misconduct.