SAO PAULO, Jan 10 (Reuters) - Brazilian power company Eletrobras (ELET6.SA) is investigating whether the collapse of two transmission towers is related to anti-government riots on Sunday after finding signs of sabotage, according to two people familiar with the probe. The towers - one of which fell on Sunday and the other in the early hours of Monday - were operated by Eletrobras subsidiaries Furnas and Eletronorte. Eletrobras, the mines and energy ministry and regulatory agency Aneel have set up a crisis committee to monitor potential threats to Brazil's power grid, according to a third source. A third tower operated by power transmission company Evoltz also collapsed, according to a report by Brazil's National Electric System Operator (ONS) on Tuesday. Eletrobras, Furnas and Evoltz did not immediately respond to requests for comment.

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