A victim of an alleged sexual assault has been interviewed by police following an incident on Saturday night (November 22) at Schoolies Festival 2014.
Police have said the alleged incident took place in the Victor Harbor area.
Operation Schoolies Festival of Celebrations 2014 police commander Robert Williams said the people involved are school leavers.
He said no arrests have been made in relation to the incident, as of 10.45am Sunday, November 23.
"I can't confirm the seriousness of it at this stage," he said.
Another sexual assault was reported, but SA Police (SAPOL) are yet to investigate.
Meanwhile, two 17-year-old school leavers from Ingle Farm and Oakden were also arrested on Saturday night after being found in possession of 100 ecstasy tablets, which police will allege were for sale.
A 20-year-old Para Hills man was also caught in possession of the illicit drug in another location.
All three were bailed and will appear in Victor Harbor Magistrates Court at a later date.
In total, SAPOL made 12 arrests during Saturday night's festivities and issued 52 expiation notices for behavioural offences.
No drivers tested positive for drink driving on Saturday, but of the 105 drivers drug tested, three returned a positive reading.
SA Ambulance Service operations manager Martin Kimber said officers treated 32 people in the south coast area on Saturday night, 27 of which were school leavers.
Eight were transferred to Flinders Medical Centre for further treatment.
Mr Kimber said St John's Ambulance volunteers treated a further 113 people.
One highly intoxicated school leaver attempted to go swimming at Hayborough on Saturday, and required medical attention after getting into difficulties.
Mr Kimber urged other school leavers to be careful and avoid the water if they have been drinking.
"The coastal waters around here are quite unsafe," he said.
Broken glowsticks were also a cause for medical attention, with 40 cases of snapped sticks resulting in the gel getting into eyes and on skin.
Mr Kimber recommended school leavers drink plenty of water on Sunday to prevent dehydration, ahead of the final night of celebrations.
Encounter Youth chief executive officer Nigel Knowles said close to 6000 school leavers attended the festival site on Warland Reserve on Saturday night.
He said Encounter Youth organisers and Green Team volunteers were pleased with the behaviour of school leavers on site.
To see updates of the weekend's activities, including daily emergency service reports, road closures, and more photos of the event, click here.