The incident is reported to have occurred in the area of Meenan Square on August 15, at around 11.20pm.
The New IRA in Derry later claimed responsibility for the attack.
In a statement, the dissident republican terror group claimed that they had fired two AK47s at a police patrol.
Sources said the Chinese AK47s were recently acquired by the group, which had lost almost all its existing weaponry in intelligence-led raids.
Detective Inspector Clara Heaton of the PSNI’s Terrorism Investigation Unit said: “We know there was a significant number of people in the area at the time.
“As our enquiries are ongoing, I want to appeal to anyone with mobile phone videos, CCTV footage, dash-cam footage, photos of the incident or anyone with information, to get in touch with us.”
The number to call with information is call 101, quoting reference number 2217 of 15/08/22.
Alternatively, you can submit a report online using our non-emergency reporting form via: http://www.psni.police.uk/makeareport/
You can also call Crimestoppers anonymously on 0800 555 111 or online at: http://crimestoppers-uk.org/