Former FBI agent reportedly confirms key details from Hunter Biden probe whistleblower

Whistleblowers allege political interference in Hunter Biden investigation.
FBI agent said Biden team got heads up on planned Hunter Biden interview, preventing it from happening.
Agent confirmed whistleblowers' claim that investigators had to wait for Hunter Biden's call.
Republicans say revelations point to two-tiered justice system favoring Bidens.
Oversight committee pursuing answers and accountability on Biden probe.