1955 seizure of the Romanian embassy in Bern

At the age of 15 he became a member of Frunză Verde ("Green Leaf"),[3] a youth organisation associated with the fascist Iron Guard, and after the end of World War II he joined the anti-communist resistance movement.

In 1954, Beldeanu began preparing the assault on the Romanian embassy: he travelled several times to Switzerland, acquired the needed weapons and tools, and held training sessions with the other members of the group (Ion Chirilă, Stan Codrescu, Dumitru Ochiu and Tudor Ciochină).

The news agency "Globe Press" pretended that Aurel Șețu was the actual head of the Romanian legation and a senior Securitate officer and that the stolen documents were ciphered messages for Moscow.

However, the Romanian government of the time accused the Iron Guard structure in exile (under the leadership of Horia Sima) and Western intelligence agencies of masterminding a fascist anti-Romanian plot with the complicity of the Swiss authorities.

In Romania, protest gatherings were staged in several towns and a large commemorative meeting held in Bucharest on the occasion of Aurel Șețu's burial.