Detectives investigating an unlicensed music event in Yate over Halloween have released 38 photos of people they would like to interview.
It is estimated up to 700 people attended the illegal music event which lasted around 17 hours.
Officers first attended the warehouse on Millbrook Road at 10.30pm on Saturday 31 October and had cleared the building at 3.10pm on Sunday 1 November.
Frontline officers were pelted with items, including bottles, as they dealt with the incident.
So far 12 people have been arrested, while two organisers have received £10,000 fines for breaching covid rules.
While most of the arrests were from the Bristol and South Gloucestershire area, three people arrested gave police addresses from Devon, Oxfordshire and Derbyshire.
Avon and Somerset Police Federation estimates the policing of the event cost the force somewhere in the region of £64,000.
Detectives are now seeking the public’s help to identify 38 people in connection with their enquiries into what happened at the event.
Detective Superintendant Lisa Simpson said: "The event we know drew party goers from outside of the Constabulary area.
"So whilst we have identified people who are known to police officers here, there are people who have probably come from other regions, that might be well know but from outside our force area."
Officers have also revealed two people who attended the rave tested positive for Covid-19.
Anyone with information about the people pictured is asked to contact us through our website, or call 101, and give reference number 5220247128.