Stefano Costantini

Stefano Costantini was born in Switzerland into an Italian family on October 1996. He was radicalized at a very young age. From 2014 to 2021, he lived in Syria to support the Jabhat al-Nusra organization. He is currently in prison in Italy.

He is believed to have been introduced to radical Islam by Altindas Alpren, a young man of Turkish origin who was born and raised in Switzerland. Alpren was actively involved in proselytizing and propaganda activities in the country.

In September 2014, after a rapid conversion to Islam and a brief radicalisation, Costantini decided to travel to Syria with Alpren. He was accompanied by Celik Servi, a German woman whom he had married shortly before. During the years they spent in Syria, they had four children.

After settling in the province of Idlib, Costantini provided essential and constant logistical support for Jabhat al-Nusra’s activities. During the trial, the defendant claimed that he had stayed in Syria only to carry out volunteer work with some NGOs. However, investigations into his social media profiles, especially Facebook, and the discovery of several photographs confirmed his involvement in the group. The photographs showed him holding rifles with his index finger pointing toward the sky.

Over time, Jabhat al-Nusra underwent an internal transformation and became Hay’at Tahrir al-Sham (HTS), currently in power in Syria. Strong tensions within the group eventually led the young man to seek a way out in order to save himself and his family. This led to his arrest on 19 January 2021 by Turkish police. Shortly after, he was voluntary repatriated by Italian authorities from the Hatay airport.

The legal proceedings began in February 2022, when the Chieti Court sentenced him to five years in prison for participation in an association for the purpose of terrorism, under Article 270-bis of the Italian Criminal Code. The verdict was later upheld by the Court of L’Aquila in November of the same year and by the Supreme Court (of Cassation) in October 2023.

However, the position of some major Western actors towards HTS and its leader, Jowlani, has changed. Some of these actors have removed HTS from their lists of terrorist organizations, including the United States in July 2025. This led the United Nations to remove the organization and all of its former component from the list of international terrorist organizations. In light of this development, Costantini is currently attempting to appeal and overturn his conviction.