One person I can think of within the Trump campaign who might have turned whistleblower is former CIA Director James Woolsey. Woolsey attended a meeting with Flynn and Turkish officials about kidnapping a Muslim cleric:
Woolsey, a Flynn Intel Group board member who was present at the September meeting, said that Flynn and the Turkish ministers went further than talking about how to lobby for Gulen's extradition, however, and discussed how they could physically remove Gulen from the country.
Reached for comment, Woolsey's spokesperson, Jonathan Franks, said that the former CIA director stands by his story. Franks confirmed that Woolsey had notified Vice President Joe Biden, through a mutual friend, of what he thought could be an illegal discussion. The Obama administration said it would not extradite Gulen until Turkey provided the necessary evidence of his complicity in the coup, but Trump has not said how he plans to address the issue, if at all.
"Ambassador Woolsey and his wife have been in communication with the FBI regarding the Sept. 19, 2016 meeting Ambassador Woolsey was invited to attend by one of Gen. Flynn's business partners," Woolsey spokesman Jonathan Franks said in a statement. "Ambassador Woolsey and his wife have responded to every request, whether from the FBI, or, more recently, the Office of the Special Counsel."
Franks clarified that the FBI has been "in communication" with Woolsey both before and after the matter was taken over by Mueller's office.