The family of Canadian filmmaker Dave Walker, whose body was found at the Angkor Wat temples in Cambodia last week, says he was murdered, and accuses Canada of failing to hold the Cambodian government accountable for a ’cover up’.

Walker did not die of natural causes as earlier reports suggest, Walker’s family said in a news release on Tuesday. In the statement, Walker’s family accused Cambodia of hiding the details surrounding Walker’s death, and accused the Canadian government of failing to seek justice for one of its citizens.

One week after Walker’s body was found, the family is still waiting for an official autopsy, and they believe the results of medical examinations on the body are being concealed, the statement said.

“All medical and law enforcement evidence strongly suggests – and none contradict – that Canadian journalist David Edward Walker was murdered,” the statement said.

The family commissioned two separate medical examinations of the body, the statement said. “Both concluded that Dave Walker did ‘not die of natural causes,’ and therefore someone was responsible for his death,” the statement said.

“The family of Dave Walker and his colleagues and many friends demand that the government of Canada immediately publicly acknowledge the truth, of which they have the full, documented evidence in their possession, that Dave Walker was murdered.”

This latest statement contradicts an earlier one from the family that said doctors were unable to determine a cause of death after a medical examination.

Walker went missing from his guesthouse in Cambodia on Feb. 14 after stepping outside to let the housekeeper clean up. A child found his body at Angkor Wat on May 1.

Walker’s body was already decomposing when it was found. Based on the body’s advanced state of decomposition, Walker is said to have been dead for several weeks before he was discovered.

According to the family’s statement, Walker’s body has been left unrefrigerated at a rural Cambodian medical facility. The family says Cambodia has refused requests to have the body transferred to Bangkok, where a proper autopsy using the most modern equipment can be performed.

His family says he did not die of a heart attack, as earlier reports suggest, and that Canada has information that proves it.

Walker’s family threatened to release the results of their medical examination if Canada doesn’t “refute the false statements” about Walker’s death.