Thames Valley Police is making an appeal in connection with a public order incident in Milton Keynes.
The force is investigating after receiving a report of a public order incident and offence of possession of an offensive weapon.
The incident happened in Ardwell Lane, Greenleys, at about 5.45pm on Thursday (13/10).
Four males appeared to be in altercation, during which a male dressed in black was seen with a knife.
Two of the males involved in the altercation were white, dressed in black tracksuits and black face coverings. They were riding a sky blue coloured dirt bike.
These two males appeared to be in altercation with another two males, who were also white, but dressed in white tracksuits and travelling on an e-scooter.
Investigating officer PC Rachel Mooney said: “I’m appealing to anyone who witnessed this altercation or has any information about the incident to contact the force.
“The easiest way to contact us is via our website or you can call 101, quoting the unique reference for this investigation, which is 43220460939.
“Alternatively, you can provide information anonymously to independent charity Crimestoppers by calling 0800 555 111 or via its website.”
