Tension between members of the band continued, however. Along with musical differences, drug use became a problem, and Santana was deeply worried that it was affecting the band's performance. Coke Escovedo encouraged Santana to take more control of the band's musical direction, much to the dismay of some of the others who thought that the band and its sound was a collective effort. Also, financial irregularities were exposed while under the management of Stan Marcum, whom Bill Graham criticized as being incompetent. Growing resentments between Santana and Michael Carabello over lifestyle issues resulted in his departure on bad terms. James Mingo Lewis was hired at the last minute as a replacement at a concert in New York City. David Brown later left due to substance abuse problems. A South American tour was cut short in Lima, Peru due to unruly fans and student protests against U.S. governmental policies.