Officers were initially called to Lyme Cross Road at 9.40pm to reports that a 17 year-old male pillion passenger on a motorbike had fallen off and suffered a head injury. The rider of the bike failed to stop.
The male was taken to hospital where a scan uncovered that he had a head wound consistent with having been shot.
He died on Monday night.
House-to-house and CCTV enquiries have been carried out in the local area. A search of the area remains ongoing this morning and high visibility patrols have also been stepped up.
Road closures remain in place at the current time at Astley Road with the junctions of Knowsley Lane / Ogle Way and Hillside Road, and Hathersage Road and road users are asked to take an alternative route.
Detective Chief Inspector Bev Hyland said: "This investigation is in its very early stages. The male was initially taken to hospital with a head injury after falling from the back of the bike and our enquiry is focused on how he suffered that injury.
"I would urge anyone who was in the area of Lyme Cross Road at around 9.30pm last night who may have seen the motorbike travelling at speed to contact us.
"The rider of the bike left the scene and I would ask them, or anyone who knows them, to contact us as a matter of urgency as they may have information which is vital to our investigation.
"I know that incidents such as this do cause concern but I want to reassure the community that we are doing everything we can to find those responsible and bring them to justice.
"Criminals involved in gun crime have no regard for anyone else and I would urge the local community to come together to help us take a stand against the use of firearms and violence on our streets and report anything they saw or heard to us so we can take action."
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