He has been named as Ross MacGillivray from Inverness.
BBC Scotland to revisit audacious scam of Met Police accountant
CCTV now with the police after Saturday's vandalism
The incident occurred in the Glenmore area sometime on Wednesday afternoon.
Four men who assaulted and robbed a man in Aviemore during the Thunder in the Glens Festival are being hunted by police.
Police Scotland has launched a new campaign targeting sexual perpetrators who groom and abuse children online.
"We owe it to the family and friends to make every effort to recover Renee and Andrew’s bodies," says DCI Brian Geddes.
"Our hopes are slim but this case will never be considered resolved until we find Renee and Andrew," say police.
Shrapnel too dangerous to remove, say experts
The victim (18) needed treatment at Raigmore Hospital in Inverness following the attack at a campsite in the early hours of Sunday.
A 74-year-old man was murdered at Keiss in Caithness on Sunday afternoon (July 3) and a woman linked to the incident was later found dead nearby.