Police will lay no charges as a result of their probe into the alleged use of the "blue magic" stimulant in harness racing.
But police said yesterday that evidence gathered in Canterbury would be made available to Harness Racing New Zealand (HRNZ), raising the potential of further action within the industry.
Aftersix months of inquiries, police involvement in the alleged drug-related fraud officially petered out yesterday.
"We've referred matters back to HRNZ," said Inspector John Doyle, of Hornby.
"Given the information we've got at the moment, it's not appropriate to lay criminal charges."
Blue magic is a banned raceday substance that is said to be capable of supercharging racehorses.
It burst into prominence in May after a crackdown in Australia and raids on six Canterbury properties by police and racing investigators.
Leading trainer Mark Purdon faces HRNZ charges of priming stable runner Light And Sound with blue magic (propantheline bromide) before two races.
In August, trainer Nigel McGrath was found guilty on three HRNZ charges of giving propantheline bromide to horses before races.
