 The botched mission furthered Castro ’ s opposition to the Grau administration , and returning to Havana , he took a leading role in the student protests against the killing of a high school pupil by government bodyguards . The protests , accompanied by a <unk> crackdown on those considered communists , led to violent clashes between protesters and police in February 1948 , in which Castro was badly beaten . At this point his public speeches took on a distinctively leftist slant , condemning the social and economic inequalities of Cuba , something in contrast to his former public criticisms , which had centered on condemning corruption and U.S. imperialism . 
