Sen. Ron Wyden (D-Ore.) said he has "obtained credible evidence" of ongoing retaliation against a whistle-blower by a manager at a power agency in Oregon.
In a letter to the Energy Department's Office of Inspector General on Thursday, Wyden called on the watchdog to "immediately resume" its probe of the Portland-based Bonneville Power Administration.
The watchdog report also said a culture of intimidation was fostered toward whistle-blowers at Bonneville.
Wyden's letter adds to the ongoing hiring scandal.
"I have obtained credible evidence of continued retaliation against a BPA Human Capital Management staffer that occurred as late as November 2013, well after the IG issued a Management Alert," Wyden wrote to the energy watchdog.
The Bonneville human resources management staffer "helped expose unlawful personnel practices," Wyden wrote.
Despite taking steps to "partially remedy" the actions against the staffer, Wyden pointed to a "deep-seated cultural problem at BPA" on adhering to lawful protections of whistle-blowers.
Wyden has long been at the forefront of the probe into Bonneville.
He has had multiple conversations with Energy Secretary Ernest Moniz and Deputy Secretary Daniel Poneman, Wyden office told The Hill.