Trump played a leading role in "birther" conspiracy theories that had been circulating since President Obama's 2008 presidential campaign. Beginning in March 2011, he publicly questioned Obama's citizenship and eligibility to serve as President. Although the Obama campaign had released a copy of the short-form birth certificate in 2008, Trump demanded to see the original "long-form" certificate. He mentioned having sent investigators to Hawaii to research the question, but he did not follow up with any findings. He also repeated a debunked allegation that Obama's grandmother said she had witnessed his birth in Kenya. When the White House later released Obama's long-form birth certificate, Trump took credit for obtaining the document, saying "I hope it checks out." His official biography mentions his purported role in forcing Obama's hand, and he has defended his pursuit of the issue when prompted, later saying that his promotion of the conspiracy made him "very popular". In 2011, he had called for Obama to release his student records, questioning whether his grades warranted entry into an Ivy League school. He also claimed in his 2011 CPAC speech that Obama's classmates "don't know who he is". When asked in 2015 whether he believed Obama was born in the United States, he said he did not want to discuss the matter further. In September 2016, he publicly acknowledged Obama's birthplace, and claimed, falsely, that the rumors had been started by Hillary Clinton during her 2008 presidential campaign.