PETALING JAYA: Former prime minister Tun Dr Mahathir Mohamad continued his attack on Datuk Seri Najib Abdul Razak, saying that most of his questions remain unanswered. He denied that his outburst had to do with the prime minister's refusal to build the crooked bridge linking Johor and Singapore. "My actions have been said to be (due to Najib's) failure in completing the crooked bridge," he posted on his blog chedet today. He added that he would not have campaigned for Najib during the 2013 general election if he had been upset with the prime minister over the bridge project. "If I am only upset about the crooked bridge, I should have called for Najib's resignation even before the 2013 general election,"he said. "Instead, I campaigned for him." Mahathir said he is aware that he is "alone" as criticism from Umno against him intensifies. "But I feel responsible to the people. When the people's money seems to be hidden from them, would it be wrong for me to ask about its whereabouts?" he said, referring to the controversial 1Malaysia Development Berhad (1MDB). He said he thought when Najib appeared on TV3 last Thursday, it would be to answer the people's questions and not just his. Mahathir also said that he had not implicated Najib in the murder of Mongolian model Altantuya Shaariibuu, but was just asking who had ordered former police commando Sirul Azhar Umar to do it.