Authorities in Peru say the gun that killed a plant healer matches one purchased by a Canadian man who was slain in the Amazon rain forest earlier this month.
The justice ministry says Sebastian Woodroffe, 41, purchased the gun on April 3 — a few weeks before Olivia Arevalo, an octogenarian from the Shipibo-Konibo tribe of northeastern Peru, was killed.
Two people have been arrested in connection with Woodroffe's death.
Peruvian authorities have said the Vancouver Island man was dragged by the neck to his death shortly after he was accused of killing Arevalo.
Prosecutors have said two suspects were identified in a video shot on a cellphone showing the moment Woodroffe was killed last week.
Officials have said forensic experts were studying Woodroffe's body to determine whether he had any involvement in her death.
Woodroffe posted online ahead of his trip to Peru, saying he hoped that an apprenticeship with a plant healer would help his goal of changing careers to become an addiction counsellor using hallucinogenic medicine.