The former prime minister claimed that his successor has launched an aggressive campaign "to demonise me and to show how much the PM is supported by the people". "But there really can be no explanation on the disappearance of the money supposedly brought back from Cayman Islands — six billion US Dollars (sic). No explanation can be made on the denial by the Swiss bank that it received money from 1MDB," Dr Mahathir said in the latest posting on his blog. "No explanation on Arul’s (Kanda Kandasamy) claim that he saw the cash and the PM explaining there was no cash. Now the cash has become units. What units? No explanation also on the inability to pay interest of 2 billion until Ananda donated or loaned 2 billion whatever. "Nor is there any explanation as to why 1MDB needs investments of USD1 billion by IPIC to pay debts to Deutsche Bank when 42 billion investments have been made. Is there no returns on the investments? And many other questions remain unanswered," he added. Dr Mahathir, who has been Najib's harshest critic over 1MDB, said he got an inkling of the alleged campaign after he received a visit at his office from "a friend", who he claimed he had helped "a lot" during his time as prime minister to the point that the latter had become a "very successful educationist" who had expanded his operations overseas — a possible reference to Tan Sri Lim Kok Wing, who was recently engaged as Najib's public relations strategist. Despite their good ties over the years, Dr Mahathir noted that his "friend" had "somewhat changed" during his last visit, having shifted positions from asking the retired politician to "do something" to "not to 'attack' the PM". "He warned that if I continue I would lose my legacy. I told him what people think of my legacy, if there is any, is not important. I am concerned at what  is happening in the country. Our good reputation is being eroded. "He repeated several times that I would lose my legacy. I really appreciated his concern. He is a friend and I felt he cared for me. We parted as friends. "But now, I understand better why he talked about my losing my legacy.

"He has been given the task of demonising me, of destroying what he calls my  legacy.

"I think he and his boss believes that if I become unpopular then my condemnation of the shenanigans involving 1MDB would be ignored by people... my ex-friend will have to do better at demonising me if he is to earn titles etc.," Dr Mahathir claimed.