The alleyway off Broomspring Close, Broomhall, facing the playground at Springfield Primary School, has been cordoned off and officers are at the scene looking for evidence.
Neighbours at the scene have said they are not sure of the nature of the crime, but reported hearing ‘loud bangs’ last night.
One mum said: “Last night before 10pm we heard what sounded like gunshots, boom boom boom.
“My child said they were at the window and they saw a man running away. I told them to come away from the glass.”
Another resident said: “I thought I heard fireworks. It was loud enough I thought someone was throwing things against my window.”
South Yorkshire Police has been contacted for more information about the incident. It is not known how long the cordon will be in place for.
This article will be updated as more information is made available.