What reasons do we have now to believe the police's story that protesters chucked bottles at them as the medic came to help him?
Because it was caught on camera.
There is footage, as shown on the news and apparently available on YouTube. It clearly shows some officers standing around a fallen body with one, possibly two attending with the assistance of a person out of uniform. The footage clearly show at least two plastic bottles flying into the shot and hitting some of the standing officers. One person, apparently a civilian, then berates someone off camera and is backed up by another person, also apparently a civilian. On face value this would appear to be a direct response to the throwing of bottles although the absence of complete context makes it impossible to be 100% certain.
It is worth noting that the original police claims about the number and type of items thrown escalated with media attention and were apparently later clarified after the reports in the news were called into question by witnesses present at the time.
Because it was caught on camera.
There is footage, as shown on the news and apparently available on YouTube. It clearly shows some officers standing around a fallen body with one, possibly two attending with the assistance of a person out of uniform. The footage clearly show at least two plastic bottles flying into the shot and hitting some of the standing officers. One person, apparently a civilian, then berates someone off camera and is backed up by another person, also apparently a civilian. On face value this would appear to be a direct response to the throwing of bottles although the absence of complete context makes it impossible to be 100% certain.
It is worth noting that the original police claims about the number and type of items thrown escalated with media attention and were apparently later clarified after the reports in the news were called into question by witnesses present at the time.