Transcript for Trump to 'look into' whether campaign was 'infiltrated'

president trump made a stunning demand on Twitter. The president saying he will officially order the justice department to investigate whether an informant working for the FBI or FBI infiltrated the campaign. Suggesting the Obama administration's involvement. At the same time, Rudy Giuliani, revealing a possible end date for an aspect of the Russian investigation. Here's David Wright. Reporter: Tonight, president trump on the warpath, demanding answers about reports that the FBI had an informant approach the trump campaign. Quote, "I hereby demand, and will do so officially tomorrow, that the department of justice look into whether or not the fbi/doj infiltrated or surveilled the trump campaign for political purposes." President trump has long insisted he has the right to intervene. You look at the corruption at the top of the FBI -- it's a disgrace. And our justice department, which I try and stay away from, but at some point I won't. Reporter: At issue now, published reports that during the 2016 campaign the FBI sent a retired American professor to talk with several key trump advisers after those advisers had been flagged for suspicious contact with Russians. Trump's FBI director, citing national security, has declined to reveal any details. The day that we can't protect human sources is the day the American people start becoming less safe. Reporter: Tonight, the justice department says it will investigate. Rod Rosenstein vows to take appropriate action if anyone did intervene for inappropriate purposes. I've always said there was no collusion, but I've also said, there's nobody tougher on Russia than me. Reporter: Russians may not be the only foreign interests trying to meddle. There are also published reports of another suspicious meeting at trump tower. An Israeli social media entrepreneur, a representative of two wealthy Arab princes and the founder of the massive private security firm blackwater reportedly met with don junior three months before the election to discuss mounting a social media campaign to help elect Donald Trump. Don trump jr.'s lawyer tells ABC news, "He was not interested and that was the end of it." Today, the president tweeted the witch hunt has given up on Russia and is looking at the rest of the world. David, late word from Rudy Giuliani telling ABC news that the Russia investigation relating to president trump will be done by September 1st? Reporter: That's right. An important distinction, they were talking about the part that relates to trump, not the whole investigation. Giuliani saying Mueller told him that a month ago, but Mueller has not confirmed that. The president's team is clearly pressuring him to wrap it up. Tom? David, thank you. Next to a major development

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