A political expert flagged what she called a "dumb move" by the Justice Department in its prosecution against former FBI Director James Comey, who has submitted a filing alleging that the case against him is vindictive or selective prosecution.

Among the documents in the Monday filing were 60 pages of examples of social media posts from President Donald Trump specifically attacking Comey. The filing became the topic of discussion on CNN, where CNN political commentator Xohitl Hinojosa weighed in.

"DOJ doesn't comment on its investigations for a reason: It could hurt the investigation or the prosecution. And the Comey case is the perfect example of this," said Hinojosa.

Hinojosa's comments came as part of CNN's "The Arena" text chain along the left side of the screen, where she called out some of the biggest flaws in the prosecution of Comey.

"Tump demanding that his AG indict Comey definitely hurts the case because it shows that this was all about politics," she added.

"Comey is also challenging Halligan's appointment as interim U.S. Attorney, which I find interesting for two reasons," she continued. "1) Trump's own lawyers challenged Jack Smith in the classified docs case. 2) It seems like a dumb move for Halligan to have been the only signature on the indictment."

Carrie Cordero, a Robert M. Gates senior fellow and general counsel at the Center for a New American Security (CNAS), recalled that no other assistant U.S. attorney was willing to sign onto the grand jury filing.

"Another reason why it's important to have an AUSA sign the indictment, and not an interim U.S. Attorney," said Hinojosa.

The reason it can be a problem is that if Halligan was removed and no one else was part of that case, it's thrown out and must be filed again. The statute of limitations has already expired, however.

Comey was indicted for lying to Congress in the Eastern District of Virginia.