Transcript for Whistleblower says he raised concerns about lavish spending by the EPA chief

investigation into a key member of president trump's cabinet and how he spent tax payer dollars. Scott Pruitt his first class travel, a $43,000 phone booth and raises. Hear the whistle blower who claims he was fired because he spoke up. Kyra Phillips and the interview. Reporter: He was part of Donald Trump's presidential campaign from the start. He's been with me right from the beginning. He's tough as hell and he's great. Reporter: Kevin Chmielewski then got a ticket to Washington, eventually becoming deputy chief of staff for EPA administrator Scott Pruitt. But tonight, Chmielewski says what he saw there, and what he said about it, cost him his job. Reporter: Chmielewski says he raised concerns about lavish spending early on. Like the $43,000 phone booth for Pruitt's office and he says a plan he over heard for the agency to rent a private jet for $100,000 a month. I said, "Do you realize we can't do that?" And she just said, once again, "This is what the administrator wanted me to look into." Reporter: The deal never happened. Chmielewski also tells us he drew the line on first class tickets to Morocco. I refused to do it. And, once again, I think that was -- some of the beginning of the retaliation. Reporter: Chmielewski said he was fired in February after raising concerns over unethical spending. The EPA says he resigned. Just four days ago, Pruitt was grilled by congress about allegations of retaliation upon anyone who defied him. I don't ever recall a conversation to that end. Reporter: When Pruitt testified to congress recently he said he was not aware of any employees being pushed out for raising red flags. Was he just straight out lying? Bold-faced lying. Kyra Phillips live tonight. Pruitt is of course under investigation by the inspector general. He's made it clear he has no plans to resign. More than 170 members of congress including several Republicans have called for Pruitt to go. He says he's here to stay. He also has the support of the president. The whistle blower said he still backs president trump. Kyra, thank you. Overseas and to a wave of

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