Poachers have used cyanide poison to kill 41 elephants in Hwange National Park in western Zimbabwe.
Zimbabwe Parks spokeswoman Caroline Washaya Moyo told the BBC that five suspects have been arrested.
People who live near the park have been told not to eat the meat of any dead animals they find.
The BBC reports there has been a rise in the killing of elephants and rhinos in parts of Africa in recent years. Their horns and tusks are used in traditional medicine in parts of Asia.
Some poachers were found with a large haul of tusks and cyanide earlier this year. Two years ago, nine elephants, five lions and two buffalo were poisoned.