April 1948, Castro travelled to Bogotá, Colombia, leading a Cuban student group sponsored by President Juan Perón's Argentine government. There, the assassination of popular leftist leader Jorge Eliécer Gaitán Ayala led to widespread rioting and clashes between the governing Conservatives – backed by the army – and leftist Liberals. Castro joined the Liberal cause by stealing guns from a police station, but subsequent police investigations concluded that he had not been involved in any killings. In April 1948, the Organization of American States was founded at a summit in Bogotá, leading to protests, which Castro joined. Returning to Cuba, Castro became a prominent figure in protests against government attempts to raise bus fares. That year, he married Mirta Díaz Balart, a student from a wealthy family, through whom he was exposed to the lifestyle of the Cuban elite. The relationship was a love match, disapproved of by both families, but Díaz Balart's father gave them tens of thousands of dollars, along with Batista, to spend on a three-month New York City honeymoon. That same year, Grau decided not to stand for re-election, which was instead won by his Partido Auténticos new candidate, Carlos Prío Socarrás. Prío faced widespread protests when members of the MSR, now allied to the police force, assassinated Justo Fuentes, a socialist friend of Castro's. In response, Prío agreed to quell the gangs, but found them too powerful to control. Castro had moved further to the left, influenced by the Marxist writings of Karl Marx, Friedrich Engels, and Vladimir Lenin. He came to interpret Cuba's problems as an integral part of capitalist society, or the "dictatorship of the bourgeoisie", rather than the failings of corrupt politicians, and adopted the Marxist view that meaningful political change could only be brought about by proletariat revolution. Visiting Havana's poorest neighbourhoods, he became active in the student anti-racist campaign. In September 1949, Mirta gave birth to a son, Fidelito, so the couple moved to a larger Havana flat. Castro continued to put himself at risk, staying active in the city's politics and joining the 30 September Movement, which contained within it both communists and members of the Partido Ortodoxo. The group's purpose was to oppose the influence of the violent gangs within the university; despite his promises, Prío had failed to control the situation, instead offering many of their senior members jobs in government ministries. Castro volunteered to deliver a speech