Investigators into the fatal shooting of an Australian woman by a police officer in Minneapolis say the officer's partner was "startled by a loud sound" just before the incident.
Justine Damond was gunned down after calling police to report a possible crime.
On a police radio recording, an officer mentions fireworks being let off near where the shooting happened.
Our US correspondent Kate Fisher reports
IN: The Minnesota
OUT: soc
DUR: 38 seconds