Prosecutor Vali Haji-Qolizadeh in the northwestern city of Khoy of West Azerbaijan was shot dead by two unidentified gunmen in front of his house on Monday night.
"Security and police forces launched an investigation into the incident in the wake of the attack and arrested four suspects in connection with the assault," Mohammadlou was quoted as saying.
In the meantime, Hojatoleslam Mohammad Mousavi, chief prosecutor of the West Azerbaijan province, said that "the assassinated prosecutor had been threatened by the outlawed PJAK terrorist group in the past days," according to the report.
Iran's western borders face security threats from the Party of Free Life of Kurdistan (PJAK), an anti-Iranian Kurdish group linked to Turkey's outlawed Kurdish Workers' Party.
No group or person claimed responsibility for the attack till now.
