A 27-year-old man remains in serious condition after he was run over while cycling before being attacked.
The cyclist was hit by a car before being attacked by people from a second car. Gloucestershire Police say he sustained several stab wounds.
The man was helped by several members of the public before paramedics arrived to take him to hospital.
Gloucestershire Police were called to Shakespeare Avenue, in Gloucester, at around 9.30pm last night (Wednesday 21 September).
Officers arrived after those involved had fled the scene, but detectives say the vehicles involved were a dark 4x4 and light-coloured saloon.
Detective Inspector Paula Hannaford said: "We're in the early stages of an investigation and at this time we believe that this likely was not a random attack on a stranger."
Police are appealing to speak with any witnesses or anyone with dashcam or CCTV footage to come forward.
Anyone with information is asked to contact Gloucestershire Police online quoting incident 487 of 21 September.
Alternatively get in contact with Crimestoppers anonymously online or by calling 0800 555 111.