His mother was a civil rights investigator for the state.
The prisoners, according to human rights investigators, were fed bread and water.
Human rights investigators were interviewing two witnesses to the killings, he said.
The vote means that Iran will no longer have a special human rights investigator assigned to it.
Human rights investigators say 28 people died in the Giciye massacre.
She only agreed to be interviewed after checking with trusted human rights investigators.
Human rights investigators said about 65 people, including the city's last two police chiefs, have been killed in drug-related violence this year.
According to human rights investigators, the prisoners were fed rarely, on bread and water.
Human rights investigators say hundreds were killed in that incident.
Human rights investigators report high rates of alcoholism and domestic violence among the affected families.