A woman is in hospital with life-threatening injuries after she was found collapsed in a street in Jaywick, Essex.
Police were called to Beach Road on Friday night to reports of a disturbance and found the woman with a serious head injury.
The woman, who is believed to be about 40, remains in a critical condition in hospital.
Two local women aged 20 and 25, a 17-year-old and a 20-year-old man from London have been arrested on suspicion of attempted murder and they remain in police custody.
Police also arrested two local men in connection with the incident, a 28-year-old on suspicion of affray and a 31-year-old man on suspicion of GBH.
"Our officers remain at the scene that is linked to the incident and I would urge anyone who has information to approach our officers and pass on anything that may help our investigation,” Stephen Jennings added.
Detectives would like to speak to anyone who saw the incident or has dash cam, doorbell or CCTV footage of what happened.