A section of Peatlands Park on the Co Armagh/Tyrone border remains cordoned off tonight (Wednesday).
It is understood that forensic investigators are carrying out a fingertip search after reports of a serious sexual assault on a woman on the park.
The PSNI say they are working to establish the circumstances of an incident.
It is understood it happened earlier this afternoon.
It has been reported that a woman was attacked at an isolated location within the popular beauty spot on the shores of Lough Neagh.
A local councillor, Sinn Fein’s Dominic Molloy, lives nearby and said local people had been stunned at what had happened.
He has urged people in the area to be vigilant, especially women walking in the area alone.
He said he understood a woman walking on an isolated path in the park had been raped.
Peatlands Park is popular with dog walkers, joggers and young mothers and Councillor Molloy said, while not wishing to alarm people, it was important people be on their guard.