The reason a box of firearms "stumbled over" by a child was partly hidden on the Roxburgh Gorge cycle and walking trail remains a mystery to Alexandra police.
The boy, who was with his father, found a military ammunitions box containing the firearms in a rocky hollow on the trail in March, Constable Sam Williams said yesterday.
They were mid-way along the Alexandra-to-Roxburgh trail. The boy's father immediately contacted police.
"After exhausting all possible lines of inquiry, and coming up with nothing, we've decided to appeal to the public to see if anyone can shed any light on it," Mr Williams said.
"It was only by chance a member of the public found the box.