Four boys were robbed at knifepoint by a gang of young men.
The victims, who are 12 and 13, were targeted in Mere Road, Spinney Hills, Leicester.
A group of youths threatened the boys with a knife before ordering them to empty their pockets and hand over their money.
None of the youngsters were hurt.
Police said today that the robbery happened near to the entrance of Spinney Hill Park, between 2.15pm and 3.15pm on Saturday, February 2.
Detective Constable Derek Johnson said: "Thankfully none of the young boys were injured during the incident, but they were left quite shaken and I am appealing for anyone with information to get in touch.
"We have already carried out inquiries in the area but we hope that members of the wider public will be able to help.
"If you were in the park area that day you may remember seeing the group of young men.
"Perhaps they also approached you or maybe you recognise them from the area where you live. If so, please don't hesitate to get in touch.
"It isn't too late to help."
The robbers are white, possibly Eastern European and 17 to 19.
One of them is of "chubby" build and was wearing a pointed woolly hat.
Contact Det Con Johnson on 101, or Crimestoppers, which is anonymous, on 0800 555 111.
