The conclusion of Robert Mueller's Russia investigation should mark the end of special counsel- or special prosecutor-led probes, Harvard Law professor emeritus Alan Dershowitz said Thursday.

Dershowitz said on Fox News' "The Ingraham Angle" that Attorney General William Barr should have made a similar statement during Barr's interview with CBS News earlier in the day.

"I think the only thing Barr should've said that he didn't say is that there should no longer ever be any special counsel," Dershowitz told host Laura Ingraham.

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"The Mueller investigation puts the final nail in the coffin of special counsels [or] special prosecutors. The attorney general could do this himself," Dershowitz continued.

Barr said earlier Thursday he thought Mueller should've reached a conclusion on the obstruction question against President Trump.

“I personally felt he could’ve reached a decision,” Barr claimed. “The [Office of Legal Counsel's] opinion says you cannot indict a president while he is in office. But he could’ve reached a decision whether it was criminal activity, but he had his reasons for not doing it, which he explained.”

Dershowitz later echoed that sentiment: "Mueller should have come to a conclusion. I think if he had come to a conclusion, it would've been there was no obstruction of justice."

He added the Justice Department has "staff people," civil servants and "full-time line prosecutors" who could fill the hole left by the absence of future special counsels' or special investigators' offices.

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"Everything that was done here could've been done by them. When the special prosecutor - the special counsel in this case - says 'I couldn't have indicted the president anyway according to the Constitution,' then what was his investigation all about?" Dershowitz asked.

Fox News' Brooke Singman contributed to this report.