St. Louis County Prosecutor Bob McCulloch gave an interview to local radio station KTRS following the news that witness 40 invented her testimony and likely perjured herself in front of the grand jury, and as we've come to expect from McCulloch, he was as unrepentant as ever about his decision to put her on the stand and on the way he conducted the grand jury hearing.

Some witnesses lied to Michael Brown grand jury, McCulloch says. So why have them testify?:

Certain witnesses who spoke before the grand jury investigating the Aug. 9 shooting of Michael Brown told obvious lies under oath, St. Louis Prosecuting Attorney Robert McCulloch said Friday.

“Clearly some were not telling the truth,” he said during an interview on KTRS 550. He added that he's not planning to pursue charges against any lying witnesses.

In his first extensive interview since the grand jury decided not to indict Ferguson Police Officer Darren Wilson, McCulloch said he had no regrets about letting grand jury members hear from non-credible witnesses.

“Early on I decided that anyone who claimed to have witnessed anything would be presented to the grand jury,” McCulloch said. He added that he would've been criticized no matter his decision.

During the interview, McCulloch referenced a woman who claimed to have seen the shooting.

This “lady clearly wasn't present,” McCulloch said. “She recounted a story right out of the newspaper,” backing up Wilson's version of events.

The criticism of that witness fits the questions surrounding Sandra McElroy, also known as Witness 40.

McElroy, who's admitted to using racial slurs and trying to raise money for Wilson, testified that she saw the entire shooting unfold, and that Brown charged the officer shortly before he was killed — a detail that has proven controversial because of conflicting reports.

MSNBC's Ari Melber, filling in for Chris Hayes this Friday spoke to former federal prosecutor Jonathan Shapiro about the latest revelation and McCulloch's response and Shapiro discussed the possible sanctions McCulloch could be facing for his decision to put McElroy on the stand.

MELBER: Why would a prosecutor say that he should put people on the stand in a grand jury that he didn't think were telling the truth?

SHAPIRO: Well, he shouldn't and no lawyer should. The rules of professional conduct prohibit it, rule 3.3 specifically says a lawyer shall not put a witness before a tribunal, including a grand jury, if the lawyer, including a prosecutor knows the person is not telling the truth. You can't do it. It's illegal. It's called suborning perjury.

If you do it the sanctions that you face are contempt of court sanctioned by your state bar, in this case the state of Missouri, or prison. You'd be indicted for it. The question is what did this prosecutor know and when did he know it?

If he knew that that witness, number forty was lying and wasn't there, he had a ethical, legal and professional duty to not put the witness on the stand. If he found out about it later, he had a separate obligation to notify the tribunal, that is go into the grand jury and say that witness lied to you.

The idea that you're able to sort of open up the grand jury witness stand to anybody who wants to have a say, like it's a group meeting or something it outrageous.

He should be disbarred for this but I'm not holding my breath for anyone to hold him accountable for his actions.