"Both the initial attending officer and the principal described the victim as an intelligent and observant boy and it is the police's position that the boy's claims are credible."
Mr Hermann said police would like to hear from the couple who may have possibly disturbed the teenager or from anyone else who may have noticed someone acting suspiciously in or around the school before the incident.
"The couple walking along Hammond St may not be aware of what has happened but they may recall seeing a teenage-looking male fleeing the trees by the school.
The teenager is described as European, aged about 15, with short black hair and wearing a grey shirt and black pants.
Anyone who may have seen someone in the area of the school at this time is asked to contact Hamilton police on (07) 858-6200.