The authorities escort one of the detainees in this morning's raid. Gianluca Battista

The Civil Guard on Tuesday arrested in Badalona four members of the same family, including 16-year-old twins who were planning to travel to Syria to join the Islamic State (ISIS) terror group.

Another brother had died in the fighting last year in Syria after joining the ranks of Harakat Sham al Islam, also known as Islamic Movement of the Levant, which is made up mostly of Moroccan nationals.

The brothers dropped out of school to begin a radicalization process with their mother’s knowledge

The twins were preparing to travel to Syria by way of Morocco when the Civil Guard arrested them in an early Tuesday morning raid, according to authorities. They had been reportedly in contact with recruiters who had made plans for their journey through Turkey.

The two brothers, who dropped out of school in Badalona, outside Barcelona, to take up Koran studies in Tétouan, Morocco, were being radicalized with their mother’s knowledge.

The Civil Guard explained that the two were under investigation for the “high grade of radicalization they were exposed to by their immediate surroundings,” above all by their mother.

Authorities made the arrests in the Llefià neighborhood, where large migrant communities live. Civil Guard officers carried out a search of the family’s home and their automobile. The suspects were taken before the High Court.

Badalona Mayor Xavier García Albiol said that Interior Minister Jorge Fernández Díaz had phoned him to inform him about the imminent police operation, Efe news agency reported.

The municipal police closed off several surrounding streets adjacent to América avenue, one of Llefià’s main arteries.

This was the fourth such raid carried out this year in Spain against jihadists and their recruits.

On March 13, the authorities arrested eight people in Barcelona, Ávila, Girona and Ciudad Real. Last year, the police and Civil Guard arrested 47 jihadists in 12 anti-terrorist operations across Spain.

The National Intelligence Center (CNI), the Civil Guard and National Police estimate that about 100 people in Spain, the majority of them Moroccan nationals, have traveled to Syria and Iraq to join ISIS and the Al Qaeda affiliate Nusra Front.