Ent trump and his legal team launching a new offensive accusing Robert Mueller of possibly setting a perjuryp for the president. Rudy Giuliani attacking the legitimacy of the special counsel. And president tron this meal day weekend tweeting, yound beautiful lives have been devastated and destroyed by the Russia investion. Tara Palmeri is at the white house. Rter: Tonight, the president's law rudyliani, attacking the credibility of the special counsel's Russia invtigation. You think that the Mueller probe is legitim Not anymore. I dot. I did wh came in. But now I E spy gate. Reporter: The president taking this memorial day weekend to pay tribute political aides caught in crosshairs of the investiga. Tweeting, who's going to G back theng and beautiful liveand others that have been devast and destroyed by the phony russiasion witch hunt? They journeyedn to Washington, D.C., with stars in their eyes and wanting to he our nation they went back home in trs! Giuliaushing the president's spy ga theory repeatedly on the Sunday talk sh What do you want to call it? Spy gate. Spy gate. Now, the spy gate, W. Reporter: There's still N evidence to support thclaims that the FBI infiltrated the trump campaign with spies to help Hillary Clinton win T election this coming after a "New York Times" report that the FBI sent a retired American professor to act as an informant on several trump adivsers after they were flagged for suicious contact with Russians. The use of such informants is routine.giuliani now saying he won let the president sit down with special counsel Robert Mueller unless he sees the cified documents from the FBI's investigation. The reality is, we T going to sit him down his is a trap for perjury.and until we are coned of that and if they don't show us these documents, we just going to have to say no. Reporteast week, the prident ordered the department of justice to brief seni lawmakers and a trump attorney on the FBI's inquiryo the trump campaign. Democratic congressman am Schiff was at that briefing, tellinc's Martha Raddatz -- There is no evideto support that spy they. This is just a piece of propaganda the president W to put out aepeat. Reporter:iuliani admitted nn the attacks on Mueller are part of an effort to sway public opion against Mueller's findings. Sang, eventually the decision will be impeach or nmpeach. Tom? Tara, thank you.