Simply replace the unfilled areas such as "" and "[date]" with your information.
You are highly commended for the way that you handled the emergency that occurred yesterday.
The [name of police department] have informed us that if you hadn't acted as quickly as you did, our customer's attack might have been fatal. Thanks to your fast reaction, [name of victim] is already out of intensive care and on the road to recovery.
We are very proud of your contribution our organization and to society at large.