The arrested man is suspected of having supplied the perpetrators with weapons prior to the attack, which took place in connection with a national football match between Belgium and Sweden on October 16, 2023.
The man was arrested at the airport in Malaga when he tried to leave the country.
"The fugitive can be sentenced to life imprisonment as he is wanted by Belgian authorities for terrorist crimes, murder, and causing serious bodily harm," writes the Spanish police in a statement.
The perpetrator in Brussels injured another Swede in the attack, after which he fled the scene. In a large police operation, the perpetrator was chased overnight. He was shot dead by police at a café the following morning.
On social media, the perpetrator had stated that he was inspired by the terrorist organization IS, and that he had deliberately chosen Swedes as targets for the attack due to the widely publicized Koran burnings that had taken place in Sweden.
According to Spanish police, the suspected accomplice of the perpetrator was arrested on Friday.
Corrected version: In an earlier version, the wrong date was stated for the attack.
