Elon Musk’s legal team is demanding to hear from Twitter’s whistle-blowing former security chief, who could help bolster Musk’s case for backing out of a US$44 billion deal to buy the social media company. Former Twitter executive Peiter Zatko – also known by his hacker handle “Mudge” – received a subpoena on Saturday from Musk’s team, according to Zatko’s lawyer and court records. The billionaire Tesla CEO has spent months alleging that the company he agreed to acquire undercounted its fake and spam accounts – and that he should not have to consummate the deal as a result. Zatko’s whistle-blower...