More than 300,000 elephants and other animals have died of cyanide poisoning in Hwange National Park, according to a conservation task force.
Some unnamed senior government officials have been implicated in the mass poisoning of the targeted elephants.
According to a report in the Standard newspaper, some government officials have been offering villagers cash to buy their silence following investigations over the cyanide poisoning of elephant salt pans and watering points.
The Zimbabwe Conservation Task Force, which is an anti-poaching organization, says it has been pushed out of Hwange National Park by security forces currently patrolling the area.
Speaking to VOA, chairman Johnny Rodriguez said last week one of his employees was arrested while doing his job and was charged with trespassing.
Rodriguez said he has since received a letter from the director of National Parks informing him that his presence in the area is unwelcome.
As investigations continue, the Zimbabwe Parks and Wildlife Management is yet to come out with a specific number of dead elephants.
Environmentalists said under the Environmental Management Act, there are provisions for outsiders to assist in such an investigation.
Environmentalist and director of the Zimbabwe Environmental Law Association, Mutuso Dhliwayo, said the law compels the government to share information concerning such incidents.
Dhliwayo said the task force should be allowed to assess the situation at Hwange National Park as it represents the interests of stakeholders.