Police are searching a propertyin South Australia's Murray Mallee regiontoday in relation to four murders.
A team from SA Police's major crime invetigation branch is leading a search of the 15-hectare property on Kenny Road, Ponde - the site of an annual sand drag racing event hosted by the Hell's Angels Motorcycle Club.
Officers are looking for a vehicle and guns connected with the deaths of Mark Boyce in 2017 and Graham Nixon, Sinibaldo Palombi and Hubert Western in 1999.
Detective Superintendent Des Bray said the property had been searched in November, but that today's search would be more extensive, and could continue "for several days".
Police will use ground-penetrating radar loaned from the Australian Federal Police's national anti-gangs squad to try to find anything they may have missed.
Officers from the Murray Mallee area, state tactical response group, mounted officers and sniffer dogs will also be involved in the search.
Mr Boyce died after being assaulted by three men on Hill Street, Elizabeth South.
One of the men has since been arrested and charged, but the other two remain at large.
Mr Nixon, Mr Palombi and Mr Western were members of the Rebels Motorcycle Club who were shot outside their clubrooms on Wright Street, in Adelaide's city centre.
Two Hell's Angels were arrested over the deaths, but the charges were later withdrawn after members of the Rebels refused to cooperate with the investigation.