According to IRNA, Iran’s official news agency, Judge Jafar Reshadati had asked for more information to be added to several sections of the investigator’s report.
Two Intelligence Ministry officials are accused of the “semi-intentional” murder of Zahra Kazemi, 54, in June this year.
"Reshadati called on the investigator ... to complete the requested parts of the file by making amendments and further supplementation," the prosecutor's office said.
Although it is unclear what portions require added information, Reshadati has requested that the file be completed as soon as possible.
Iran's Khatami is under increased
pressure to fulfill reforms
An autopsy report stated that Kazemi, a Canadian journalist of Iranian descent, was killed by blows to the head while in detention. She had been detained for taking photographs outside a Tehran prison.
Her death has sparked a diplomatic row between Canada and Iran – resulting in Ottawa recalling its ambassador in protest.
In a separate incident, Iranian officials have accused Canada of revenge killing in the death of an Iranian youth killed by police last month.
Canada has been critical of the original investigator’s report saying it doubted that two low-level officials were the only people behind Kazemi’s death. Meanwhile the Intelligence Ministry denies any involvement.
Hardliners in Iran control the judiciary and other powerful state institutions, but this case is seen as a test of reformist President Muhammad Khatami and whether or not the perpetrators will be convicted.