Washington, May 21 (IANS): US President Donald Trumps lawyer Rudy Giuliani has said that special counsel Robert Mueller hopes to finish by September 1 the investigation into whether Trump obstructed the Russia inquiry. He added that waiting any longer would risk improperly influencing voters in Novembers midterm elections.

The office of Mueller shared its timeline about two weeks ago amid negotiations over whether Trump will be questioned by investigators, adding that Mueller's office said that the date was contingent on Trump sitting for an interview, NYT reported quoting Giuliani.

A spokesman for the special counsel's office declined to comment.

Wrapping up the obstruction case would not signal the end of Mueller's work. That is one piece of his broader inquiry, a counterintelligence investigation into Russia's campaign to interfere in the 2016 Presidential election and whether Trump associates coordinated with it.

Counterintelligence investigations are used to gather information quietly about the activities of foreign powers and their agents -- sometimes for years -- and can result in criminal charges.

"We want the concentration of this to be on Comey versus the President's credibility, and I think we win that and people get that," Giuliani said.

He also hoped that the Justice Department would open a criminal investigation into Comey for perjury and his role in the disclosures in 2017 about his encounters with the President that prompted Mueller's appointment.

Giuliani said Comey had damaged his credibility during his recent book tour and was an unreliable witness. Trump's lawyers have long said that Comey's accounts of their interactions cannot be trusted.