On this day in conspiracies

In the early hours, an unexploded backpack bomb recovered from the trains is examined at a police station in Vallecas. It yields a mobile phone and SIM card that lead police to a Madrid phone shop and to the first arrests, and it later becomes the central object of the conspiracy theory.

Maduro says the state will convene a commission of 'the world's best scientists' to investigate whether Chavez was poisoned. Oncologist Elmer Huerta tells CNN en Espanol the poisoning idea has 'absolutely no scientific' basis.

UK Prime Minister Theresa May tells Parliament that the agent has been identified as a Novichok, a military-grade nerve agent developed by the Soviet Union, and that it is highly likely Russia is responsible. Britain and allied states go on to expel more than 150 Russian diplomats.

Chinese foreign-ministry spokesman Zhao Lijian tweets that 'it might be US army who brought the epidemic to Wuhan,' pointing to the October 2019 Military World Games. CNN and CBS report that he cites no evidence and draws on a fringe website; Beijing does not formally endorse the tweet as its official position.