Two boys were threatened with a knife before having their bikes stolen in a Northampton park last weekend.
The children were playing football when they were approached by two boys who asked to borrow their bikes.
When they refused, they were threatened with a knife and the offenders stole their bikes.
The incident happened on Saturday, May 13 between 2pm and 2.30pm on the Racecourse.
The offender with the knife was about 14-years-old, around 5ft with a medium build, wearing a grey hoody and black jogging bottoms. The other was about 16, 5ft 10in with a skinny build, wearing a black hoody.
Two people were arrested in connection with the offence and have been released from custody pending further inquiries and the bikes have been recovered.
Witnesses, or anyone with information, are asked to contact Northamptonshire Police on 101 or Crimestoppers on 0800 555111.