Last week, we learned that the Manhattan District Attorney’s Office planned to indict former President Donald Trump within the next week. It is unclear at this time who the witness would be.

Trump said on Truth Social that the “most significant witness” would testify before the grand jury on Monday. Trump claimed that the surprise witness was a “respected attorney”.

“THE INFORMATION HE WILL PRESENT WILL SUPPOSEDLY BE CONCLUSIVE AND IRREFUTABLE! WITCH HUNT!!!” Trump posted in all-caps because… well, why not?

A source close to the investigation says that Robert Costello, Rudy Giuliani’s lawyer, will appear before the grand jury Monday. This is to undermine Cohen’s credibility.

Cohen is a former Trump lawyer who was a star witness in the prosecution. He will testify against Costello Monday.

“I don’t have any idea as to why, at this stage, would you even need that,” Cohen told Insider. “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 s—t.”

According to Trump, Costello has “conclusive and irrefutable” evidence that should exonerate him. What is this evidence? Who knows? But experts have already said that the case against Trump is ridiculously weak. But hey, maybe Costello can provide solid evidence that will make it impossible for even a partisan grand jury and a partisan prosecutor to go forward with bogus charges.

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

One mystery has been solved. But what next?