A teenage boy was allegedly assaulted at the Mandurah Aquatic and Recreation Centre earlier this month.
Mandurah detectives said a man is currently assisting police with inquiries in relation to the alleged assault.
During the afternoon of Friday, November 16 a teenage boy was allegedly assaulted by an elderly man at the MARC on Pinjarra Road.
Shortly afterwards the man re-approached the victim and spoke with him briefly before leaving.
It's not yet know if any charged will be laid or if the man assisting police will be taken into custody.