The man was arrested for his "full affiliation and commitment to the terrorist organization Isis" and "the indoctrination activities he carried out in his close circle and intense self-indoctrination which he submitted himself to" the Policia Nacional said.
The Spanish citizen watched videos containing "very violent and explicit" content and his ability to access them "demonstrated an important (level of) skill with the web, as this propaganda material inciting the carrying out of attacks is distributed through a communications network that is very difficult to access in order to make it tough to locate".
Investigators found that the man took exceptional security measures in order to avoid being detected by police, maintaining private profiles on social media and avoiding public comments in favour of Isis, only showing his support in private meetings designed to indoctrinate others.
The Spaniard was also in direct contact with people convicted for being part of Isis who indoctrinated then sent fighters from Melilla and Morocco to conflict areas.
Police said his arrest meant the neutralization of a "potential threat" as the man could have carried out attacks "as demanded by Isis". The operation in which he was arrested is still ongoing, and statements will be heard from two further people who expressed support for Isis after being indoctrinated by the arrested man, they concluded.