The detainee is a pensioner from Spain's northern city of Miranda de Ebro in Burgos province, Spanish TV reported. Until his retirement, the man worked as a civil servant in the city council of Vitoria-Gasteiz. In recent years, he has not been officially associated with any political group.
The suspect does not have any links to any political groups in Russia, Spanish press said later on Wednesday. He is expected to stand trial on January 27.
The court will consider the case as a possible terrorism offense, the report said, adding that the man will be tried as the perpetrator of all the mailings.
On Sunday, US press claimed reported that Russian security service officers had allegedly coordinated supporters of white supremacist groups to mail bomb parcels in Spain. The Russian embassy, in turn, said that Spanish media were very actively promoting this article, although it did not contain any evidence.
The Russian Embassy in Spain said on Wednesday that the detention of the Spaniard demonstrated the Russophobic nature of some Western media.
"Commentary by the Russian Embassy in Spain on yet another revelation of the propaganda and Russophobia of some Western media. We share the reaction of readers of the Spanish press when they learned that accusations against Russia of sending letters with explosives, so actively disseminated in Spain, have been refuted: some mock anti-Russian propaganda, others share the belief that they have completely lost confidence in the media," the embassy said in a statement.
In November and December 2022, a total of six letters with explosive devices inside were discovered in Spain. They were, in particular, addressed to Spanish Prime Minister Pedro Sanchez, Defense Minister Margarita Robles, and the US and the Ukrainian embassy in Madrid. One employee of the diplomatic facility was injured as a result of the incident involving the letter.
Representatives of the Spanish law enforcement agencies have said they had no evidence of Russia's involvement in the crimes. Moscow has also denied all allegations it was behind the incidents.