Transcript for 'I'm not cooperating. Arrest me': Ex-Trump aide tells special counsel
Sam nunberg today on live TV saying he will burn the grand jury subpoena he received from Mueller, rather than turn over the documents he has demanded, saying, let him arrest me. But nunberg then went on to make those bold suggestions about his former boss. What he says Donald Trump allegedly knew. We begin with ABC's chief justice correspondent Pierre Thomas tonight. Reporter: Tonight, a former trump campaign adviser, Sam nunberg, is defying the special counsel, going on cable television today to say he will not comply with a subpoena to appear before a grand jury in Robert Mueller's investigation. When asked, what could happen to him? I'm not cooperating. Arrest me. Reporter: But Sam nunberg went on to make a stunning suggestion about Robert Mueller and his team. When asked if he thinks they found something on his former boss, Donald Trump -- Do you think that they have something on the president? I think they may. What? I think he may have done something during tlection, but I don't know that for sure. Why do you think that? I can't explain it unless you were in there. Reporter: Nunberg suggesting on yet another cable show that he believes the president knew about the trump tower meeting with the Russians, a meeting with a foreign adversary to get dirt on an American candidate, Hillary Clinton, something the white house has denied. Do you think that Donald Trump says -- president trump says he knew nothing about the meeting. Do you think that's true? No. You don't think that's true. No. It doesn't -- and Jake, I've watched your news reports. You know it's not true. He talked about it the week before. And I don't know why he did this. All he had to say was, yeah, we met with the Russians. The Russians offered us something, and we thought they had something, and that was it. I don't know why he went around trying to hide. He shouldn't have. Reporter: Nunberg said he's already been interviewed for five and a half hours by the special counsel, and that why should he have to turn over more? They wanted every single e-mail I had with Roger stone and with Steve Bannon. Why should I hand them e-mails from novemberst, 2015? Reporter: Nunberg, who was fired from the trump campaign, . They asked me, did you hear people speaking Russian -- Who? I did not hear people speaking Russian in the trump office, okay? That's ridiculous. Reporter: Nunberg says now Mueller has subpoenaed all documents, e-mails, texts and otherwise. Any communications he may have had with a who's who among trump campaign officials and white house aides. They sent me a subpoena where they asked me, after November 1 of 2015, did I communicate with Carter page, Corey Lewandowski. I mean, I despise Corey, why would I communicate with him? Hope hicks. Reporter: But tonight, he's refusing to release them. I'm spending a lot of money on legal fees. A lot of other people are. And granted, Donald Trump caused it, because he's an idiot. Reporter: Late today, the white house was pressed about nunberg's bold suggestion that the special counsel may, quote, have something on the president. He's incorrect. As we've said many times before, there was no collusion with the trump campaign. Anything further on what his actions are, he hasn't worked at the white house, so, I certainly can't speak to him or the lack of knowledge that he clearly has. Bold claims about the president tonight. Pierre Thomas with us now live. And just now, nunberg going on cable TV yet again to say he was also offered immunity by the special counsel, apparently turning it down and now refusing to cooperate, Pierre? Reporter: That's right. He just talked about being offered immunity, but he's still saying he won testify. That means he could be held in contempt of court and could face jail time. Pierre Thomas leading us off on a Monday night.
This transcript has been automatically generated and may not be 100% accurate.