Officers had been called at dawn on Thursday to the A458 at Golfa, a mile from Welshpool, where a car had collided with the deer.
The animal had to be put down by a vet.
Dyfed Powys Police appealed: “Some time between 8am and 8.50am the deer has been removed from the road by a member of the public.
"Due to the level of medication administered by the vet, the deer is a health risk and we’re concerned the person who found it might plan to eat it. If this was you, please call 101 and an officer will come and collect the animal to be properly disposed of.”