Violent muggers targeted people at random in Harrogate in the early hours of Saturday morning - forcing them to hand over phones and cash.
Police say seven victims have come forward to say they were attacked in and around the town centre on the night of Friday, July 4 and into the early hours of Saturday, July 5.
But detectives believe other victims may have been targeted and have issued an appeal calling on them to come forward.
They are also appealing to anyone who witnessed any of the incidents to get in touch.
Police say the victims were targeted randomly, threatened with violence and, in some instances, property including mobile phones, bank cards and cash were stolen.
Three people, including a 17-year-old boy, and two men aged 21 and 24, have been arrested in connection with the incidents and given bail while investigations continue.
Anyone with any information is asked to contact North Yorkshire Police on 101 and ask for Harrogate CID reference 12140110103. To remain anonymous, call Crimestoppers on 0800 555111.