Police are trying the trace the source of a video circulating online which appears to show two people engaging in a sexual act in Bicester.
On Friday May 17 officers were made aware of a video of an alleged sexual act in Pingle Field.
They would like to speak to anyone who saw the incident or who has seen the online video.
Officers believe the offence of outraging public decency took place on May 11 during the daytime, but are unclear what time it happened.
Police are asking people not to share the video if they see it, but to flag it as inappropriate content.
As part of the ongoing investigation, a 30-year-old woman from the town has been arrested on suspicion of outraging public decency and on suspicion of possession with intent to supply class A drugs.
Investigating officer Detective Inspector Jon Capps said: “We would like to speak to anyone who was a witness to this incident.
“This happened in daylight hours in a very public area, and we believe there were many witnesses to this offence who have yet to come forward to police.
“We would also like to speak to the person who filmed the incident to assist with this investigation.
“Incidents of this nature are rare but we would like to remind and encourage anyone who witnesses incidents of this nature to report them to the police.”
If you have any information about this incident please contact the non-emergency police number 101 quoting the reference 43190149071 or make a report online.
If you do not wish to speak directly with police, you can call Crimestoppers anonymously on 0800 555 111.