A former University of South Florida professor is being subpoenaed for a third time in a case investigating Muslim charities and businesses. That's according to his lawyer, Jonathan Turley, who wrote about the development on his blog. Turley says the subpoena puts Sami al-Arian at risk for another contempt of court sanction that threatens to extend his jail time yet again.Prosecutors alleged that al-Arian was a leader of the Palestinian Islamic Jihad. But his 2005 trial ended in an acquittal on some counts and a hung jury on others. He eventually pleaded guilty to lesser charges. Since then, prosecutors in Alexandria have sought his testimony for a related investigation. But al-Arian has for nearly two years refused to testify despite a grant of immunity. His prison time would have already expired if not for the contempt of court violations.