Swedish authorities arrested an Iranian citizen suspected of connections to the execution in 1988 of around 3,000 socialist prisoners in Iran, according to local media on Wednesday, Anadolu reports.
Citing security sources, Swedish media reported that a 58-year-old Iranian citizen was detained in Stockholm's Arlanda airport.
The suspect was brought before a court and remanded in custody for "violating international law".
Although the suspect was not officially named, some news outlets suggested he was former prosecutor Hamid Nouri.
The suspect's lawyer, Lars Hultgren did not respond to questions, the local media added.
In 1988, the Iranian government cracked down on socialist and communist former allies against the Shah regime.
The process lasted for around five months and resulted in the execution of around 3,000 people from socialist and communist groups.
This arrest in Sweden is the first international case regarding those executions in Iran.