Witnesses to the alleged murder of a Mt Gambier man in a brawl are being threatened over social media, police say.

Rex Court, 32, died in hospital after a brawl involving more than a dozen people on Saturday night and a 15-year-old boy has been charged with murder.

Detective Senior Sergeant Mark McEachern says police have been advised some witnesses or potential witnesses have been threatened or intimidated over social media.

He says charges could be laid.

"We are closely monitoring this situation and warn that any such threats or intimidation may constitute a criminal offence and we will be investigating any such reports," Det McEacheern said on Thursday.

He said police were happy with progress in the investigation of Mr Court's death, with 25 calls received by Crime Stoppers, and detectives expected to make further arrests.

AAP

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