They 're thinking of recruiting , sending fighters to aid the ISIS terrorist group . The cell 's suspected leader had been a prisoner at Guantanamo Bay , Cuba , ministry said . The arrests came just ahead of the proclamation of Spain 's new King Felipe VI on Thursday . This week , thousands of police and security forces will be on alert throughout Madrid ; King Juan Carlos , 76 , Spain 's head of state and commander in chief , formalizes his abdication Wednesday , leading to the proclamation of his son , Crown Prince Felipe , 46 , as the new King , in a nation where the elected government runs the country . This week , thousands of police and security forces will be on alert during coronation festivities .
They 're thinking of recruiting , sending fighters to aid the ISIS terrorist group . The cell 's suspected leader had been a prisoner at Guantanamo Bay , Cuba , ministry said . The arrests came just ahead of the proclamation of Spain 's new King Felipe VI on Thursday . This week , thousands of police and security forces will be on alert during coronation festivities .