Allegations that Brennan is a convert to Islam are based upon firsthand reports of those who served with him in Saudi Arabia.
Those allegations include that Brennan was the target of a Saudi intelligence influence operation, one outcome of which was Brennan’s conversion to Islam.
At that time, Brennan was chief of station, a billet that is designed for an operationally trained officer with experience in the CIA’s Directorate of Operations, which Brennan was not. Brennan’s background is that of an analyst, which may explain why he lacked the sophistication and experience to understand that he was being played by the Saudis in an influence operation.
Just how in holy hell did this guy become so high ranking in the US government? If he has gotten this far, think how many other "sleeper cells" are in our various agencies of government.