Can Spanish police arrest me based solely on a Diffusion rather than a Red Notice?

Yes. Diffusions are less formal than Red Notices but are still circulated through INTERPOL channels and can prompt arrests in Spain. Spanish law enforcement treats Diffusions seriously, particularly when issued by countries with active extradition treaties. The key difference is procedural: Diffusions bypass INTERPOL’s General Secretariat review, meaning they often contain more deficiencies and are easier to challenge before the CCF. If detained on a Diffusion, the requesting country must still submit a formal extradition request within the statutory timeframe — typically 40 days under Spanish law — or you must be released.