A Swiss national who was accused of spying by Tehran was found dead in prison in what officials say was a suicide.
The Mizan news website, which is affiliated with Iran's judiciary, said the Swiss citizen had been "arrested by security agencies for espionage and his case was under investigation" when he took his own life at the prison in the eastern city of Semnan on January 9.
The Swiss foreign minister confirmed in an e-mail to RFE/RL's Radio Farda that Switzerland had been informed of the situation and is seeking further details.
"The FDFA (Swiss Foreign Ministry) confirms the death of a Swiss citizen in Iran. The Swiss Embassy in Tehran is in contact with the local authorities to clarify the circumstances of the death in an Iranian prison," said ministry spokesman Pierre-Alain Eltschinger.
"The FDFA is providing consular protection to the relatives. At this stage, the FDFA cannot provide any further information."
Mizan quoted Mohammad Sadeq Akbari, the chief justice of Semnan Province, as saying the individual was being held in a cell with another prisoner and took his life when the cellmate was not present.
Akbari did not name the Swiss citizen or provide further details, saying an investigation is being conducted and so far "suicide is certain" as the cause of death.
No details of the charges against the Swiss citizen were revealed.
Several European countries and the United States have characterized the Islamic republic's arrest of Western citizens as "hostage diplomacy," claiming Tehran uses such detentions as bargaining chips in negotiations with the West.
Three years earlier a Swiss diplomat died under mysterious circumstances.
Iranian media said the person died from a fall from a high-rise building just outside of Tehran. Swiss authorities did not identify the victim, nor did they give details on the incident.
In December, the Swiss Attorney General's Office said the case of the diplomat's death had been closed and that an investigation had not proven any "criminal interference by a third party."
The investigation reportedly was complicated by the absence of organs in the victim after an initial autopsy was performed in Iran.
Switzerland has represented the United States diplomatically in Iran since Washington and Tehran cut ties in the aftermath of the 1979 Islamic Revolution.