MADRID — Spain’s National Court on Wednesday dealt a setback to victims seeking justice for the abuses of the Franco dictatorship by refusing to extradite to Argentina a former police inspector accused of torture during the 1970s, the final years of the Franco regime.

The case of Antonio González Pacheco, a former police inspector in Madrid once known as Billy the Kid, has renewed attention on official mistreatment during the Franco era, as well as on the post-Franco amnesty law that prevents victims from having their cases heard in Spanish courts. Many victims have taken their claims to Argentina, where a judge has invoked the legal principle of universal jurisdiction, which holds that certain crimes, like crimes against humanity, transcend borders.

But in Wednesday’s opinion, the National Court in Madrid ruled that the 13 counts of torture brought against Mr. Pacheco in Argentina did not qualify as crimes against humanity because they were “isolated” rather than part of a systemic persecution. The court also noted that in Spain, the statute of limitations on torture expires after 10 years.