The Constitution does not explicitly provide for special counsels or special prosecutors, Dershowitz said Tuesday on "The Ingraham Angle."
He added such offices are "inconsistent" with the founding document, adding that there wasn't a pretense for the several-hundred-page conclusion to the investigation into President Trump.
Dershowitz also claimed Democrats have no legal right to have Mueller testify before them.
"Prosecutors have a right to say only one thing: We have concluded there's no evidence sufficient to charge the president with Russian collusion or obstruction of justice, period. I'm taking no questions, I'm making no public report. I'm giving my findings to the attorney general.
"No prosecutor should go beyond that."
Earlier Tuesday, House Democrats passed a civil enforcement resolution they said effectively holds Attorney General William Barr and former White House counsel Don McGahn in contempt of Congress.
Barr previously skipped a hearing on the findings of the Mueller report after Trump asserted executive privilege.
On Monday, House Judiciary Committee Chairman Jerrold Nadler, D-N.Y., announced he had reached a deal with the Justice Department to access key documents related to potential obstruction of justice, and that he would pause efforts to have the full House vote on that measure.
Fox News' Gregg Re contributed to this report.