• A Trump indictment in New York now remains on hold until possibly two more grand jury witnesses testify.

• One witness is Rudy Giuliani lawyer Robert Costello, ex-attorney for key prosecution witness Michael Cohen.

• Cohen himself may then be called by the prosecution to rebut Costello, Cohen told Insider.

Monday's surprise grand jury witness in the New York "hush-money" investigation into Donald Trump is Giuliani lawyer Robert Costello, a source familiar with the investigation confirmed to Insider.

Star prosecution witness Michael Cohen is also making himself available Monday, in case Manhattan prosecutors decide to call him before the grand jury to give rebuttal testimony, Cohen told Insider.

News that as many as two witnesses — Costello and Cohen — may now need to testify before the grand jury can vote provides new clues to the timing for any indictment.

The grand jury meets in secret on Monday, Wednesday and Friday afternoons, and will next convene for three hours on Monday.

The grand jurors must hear all evidence and then be informed of the relevant law — called being "charged" — by prosecutors before they can begin deliberations and voting.

If these tasks are not completed in three hours, grand jurors would return Wednesday afternoon to continue working.

Trump on Saturday had called on his supporters to "protest and take our nation back" in a Truth Social post that included his own prediction that he "will be arrested on Tuesday," March 21.

The grand jury, which is between 16 to 23 members in number, could reach a vote by the end of the three-hour session on Monday, but this last minute expansion of the witness list makes a Tuesday arrest unlikely.

Costello is a former legal advisor to Cohen, and will appear before the grand jury "solely to undermine" Cohen's credibility, sources familiar with the matter told The New York Times, which first broke the identity of the mystery defense witness testifying Monday.

News of Cohen being on call Monday as a potential DA rebuttal witness was first broken by MSNBC.

"I don't have any idea as to why, at this stage, would you even need that," Cohen told Insider, referring to Costello's testimony.

"And I don't want to speculate," he added. "Nor do I want to start doing what Donald does, which is just to put out more shit."

In November 2019, Rudy Giuliani hired Costello to represent him after the House of Representatives opened an investigation into his business dealings with Ukraine, The Wall Street Journal reported at the time

Costello did not immediately respond to requests for comment from Insider.

Trump has repeatedly and stridently denied any wrongdoing in the hush-money matter. 

It is unclear if Costello is testifying on the request of Trump defense lawyers or on the request of grand jurors. Both are possible, according to former Manhattan financial-crimes prosecutor Diana Florence.

Read the original article on Insider