A Venezuelan accountant pleaded guilty Wednesday to charges that he helped a Connecticut-based hedge fund adviser attempt to cover up a massive, five-year pyramid scheme that could cost investors hundreds of millions of dollars.

Juan Carlos Guillen Zerpa was accused of falsifying a document to throw off federal investigators targeting Francisco Illarramendi, a Venezuelan-American financier who used unregistered hedge funds in Stamford, Conn., as cover for one of the biggest frauds in state history.