I have three questions:
Firstly, if you physically crush a hundred or so people into a small space, forbid them to leave for hours on end, deny them access to food and water, in conditions that any reasonable person would think hazardous to health, how can any death in those circumstances be plausibly described as "natural"? A natural death is having a heart-attack waiting for the bus, or passing peacefully in your sleep. It´s not keeling over whilst being penned in by dozens of armoured, baton-wielding police.
Secondly, are the deaths of 30 year old males (who are apparently healthy enough to consider it sensible to attend potentially physically demanding protests) of "natural causes" unrelated to police brutality and particular police crushing tactics so common, and the deaths of people detained by the police so uncommon, that your first reaction to learning of such an event would be to automatically accept the explanation unquestioningly rather than to smell something fishy and speculate as much?
Thirdly, given the police force´s history of lying about similar incidents, including the Hillsborough disaster, for which one newspaper was forced to apologise for repeating police fabrications without question, and the De Menezes affair, in which the police were caught repeatedly and deliberately distorting the facts to justify the killing of an innocent man, when reporting such a story would you repeat their unlikely claims of protesters throwing bottles at paramedics rushing to help a hurt comrade, failing to provide the police as the source of the information, failing to quote any person at all, simply reporting it as fact or would you treat the accusation with caution; aware that it both sounds false and eminates from an organisation with a long history of lying to cover their mistakes and excesses?
If your answered these questions with (a) easily (b) accept unquestioningly or (c) report it as truth, so undeniable in fact that you needn´t even provide a quote or source; then congratulations, you must be a journalist for either the BBC, The Guardian, The Times, The Daily Mail, The Sun or any other major national news outlet.