The sick prankster is said to have phoned a number of celebrities, as well as the pathologist who carried out the autopsy on Heath and the funeral directors who took care of his remains.
The imposter is said to have tried to persuade John to give him money to fund a flight to the United States and pay for his stay at the Carlyle hotel on Madison Avenue.
But when Tom, 45, spoke to him, he wasn't fooled by the cruel conman.
'They spoke briefly but he realized the caller was an imposter almost immediately and he hung up,' the source tells US weekly.
Police Commissioner Ray Kelly tells The Huffington Post that detectives were sent to Heath's wake on Friday in the hope of catching the fraudster. But they do not yet know his identity.
Meanwhile Heath's real dad Kim visited his son's Manhattan apartment early this morning.
He was escorted through a back entrance by security before spending an hour inside. He also saw the memorial made by residents in the back garden and basement.
Kim will be flying back to Perth for the private funeral in the next few days.
The cause of death remains inconclusive but further tests are due to be carried out.
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