No one has yet been arrested for the deed in Iran's capital Tehran, where Hamas' political leader Ismail Haniya was killed, according to Iran's judiciary.
The investigation has been initiated and results will be announced as soon as there is something to report, says the judiciary's spokesperson Asghar Jahangir.
No arrests with connections to this case have been made, he says.
Both Iran and the terrorist-listed group Hamas accuse Israel of the attack last Wednesday. Ismail Haniya was in Tehran in connection with the installation of the country's new president.
Much is still unclear about Haniya's death. According to Iran's Revolutionary Guard, Haniya was killed by a "short-range projectile". Earlier reports stated that the Hamas leader was killed by a bomb that was smuggled into his room in Tehran.