Parents were warned not to take their children to the playground after school on Friday after reports of a knifeman in the park.
The police helicopter was scrambled after reports of three men chasing another man through Queens Park at 3pm – just as schools were due to finish.
Officers arrived and arrested a 23-year-old Brighton man, and a knife was seized. But the other suspects were not caught.
An investigation is now underway to locate them. The 23-year-old has been bailed with conditions, pending further enquiries.
As the helicopter circled over Queens Park, Hanover and Kemp Town, both Queens Park and nearby Tarner Park were uncharacteristically empty.
It’s believed a parent had seen a man with a knife and word had spread around other parents and after school clubs in the area.
Witnesses or anyone with any information or footage is asked to contact police online or call 101 quoting serial 820 of 18/10.
