[4][5][6] In the following years, Dehnavi obtained a degree in Islamic law, and in the late 1990s re-entered the Iranian judiciary system, gradually rising to the rank of prosecutor and judge by the early 2000s.
[10] Among journalists and activists tried by him were Akbar Ganji, Shiva Nazar Ahari, Ezzatollah Sahabi, Fereshteh Ghazi, Amir Farshad Ebrahimi, and a number of students from the Office for Strengthening Unity.
Kianush Sanjari published an open letter accusing Dehnavi of presiding over torture and mistreatment of prisoners, Ali Afshari cited Dehnavi as "a clear example of the non-independence of the judiciary from the security services", and Reza Alijani stated that "...intelligence services had just begun appointing puppet judges to the Revolutionary Courts: usually select individuals with an array of personal weaknesses, be they moral, financial or political.
[13] Also in 2007, Dehnavi was involved in the imprisonment of Iranian-American academic Haleh Esfandiari, detained for nearly three months in Evin Prison under accusation of "endangering national security through propaganda against the system and espionage for foreigners".
[15][16][17] As judge in Branch 26 of the Revolutionary Court of Tehran, he handled many cases of detainees after the 2009 Iranian election protests and repeatedly threatened the families of the accused to remain silent.
[25][26] In 2014 Dehnavi was among six Iranian judges accused by human rights organisations of leading a crackdown on journalists and political activists, acting under the influence of the regime's intelligence and security apparatus; "losing their judicial impartiality and overseeing miscarriages of justice in trials in which scores of journalists, lawyers, political activists and members of Iran's ethnic and religious minorities have been condemned to lengthy prison terms, lashes and even execution... common violations by the judges include holding trials behind closed doors, lasting only a few minutes and without essential legal procedures, intimidating defendants, breaching judicial independence by acting as prosecutors themselves and depriving prisoners of access to lawyers".