Four rights groups have called on Iran to end its “cruel” campaign of harassment and intimidation against the families of detainees who have died under suspicious circumstances.

In a joint statement on March 13, Amnesty International, Human Rights Watch, The Center for Human Rights In Iran, and Justice For Iran said the bereaved families are facing reprisals for seeking truth and justice regarding the deaths of their loved ones.

There have been at least five deaths in custody in Iran in past weeks, the rights groups said, adding that in all those cases, Iranian judicial and security authorities have pressured the families to silence them.

“Family members have been subjected to various forms of harassment and intimidation, including before being informed of the death of their loved ones,” the statement said.

“Their lawyers have also received threats for pursuing legal action, faced pressure to withdraw their representation, and, in at least one case, a lawyer has been detained for speaking to the media,” it added.

“The authorities should ensure that if there is sufficient evidence of unlawful deaths in detention, the perpetrators responsible will be prosecuted and punished,” the rights groups said.

They called on Iran to “immediately” lift the travel ban against Maryam Mombeini, the wife of an Iranian-Canadian environmentalist who died in custody two weeks after being arrested on espionage charges.

Authorities say that Kavous Seyed-Emami, a professor of sociology and the managing director of the Persian Heritage Wildlife Foundation, committed suicide in prison.

The family and activists have denied the charges against Emami and questioned the suicide claim, calling for an independent investigation.

Emami’s two sons were allowed to fly to Canada on March 7. But they said that authorities confiscated their mother's passport.