In October 2005, Baltimore resigned the office of the president of Caltech, saying, "This is not a decision that I have made easily, but I am convinced that the interests of the Institute will be best served by a presidential transition at this particular time in its history..." Soon after, at Baltimore's request, Caltech began investigating the work Luk van Parijs had conducted while a postdoc in Baltimore's laboratory. Van Parijs first came under suspicion at MIT, for work done after he had left Baltimore's lab. After van Parijs had been fired by MIT, his doctoral supervisor also noted problems with work van Parijs did at the Brigham and Women's Hospital, before leaving Harvard to go to Baltimore's lab. The Caltech investigation concluded in March 2007. It found van Parijs alone committed research misconduct, and that four papers co-authored by Baltimore, van Parijs, and others required correction.