Madrid ( CNN ) -- An Iranian and three Spaniards who secretly tried to export to Iran industrial equipment that could be used to make missile parts or enrich uranium have been arrested in Spain , the Civil Guard said Monday in a statement . The European Union and the United States ban the export to Iran of certain dual-use machinery and technology that could be used to aid Iran 's military program . The four suspects were arrested April 1 . The Iranian man , 47 , was detained in Palma de Mallorca on Spain 's Balearic Islands , and a judge remanded him to prison April 3 on suspicion of contraband in dual-use material , belonging to a criminal organization and money laundering , said a Civil Guard captain with the intelligence division , who spoke on condition of not being identified . The three Spaniards are from the same family . The father , in his 70s , and a son , in his 40s , were arrested in Tarragona , in eastern Spain . A daughter , in her 40s , was arrested in nearby Barcelona . They face the same preliminary charges , but the judge released them on the condition that they do not leave Spain and report regularly to authorities , the captain said . The charges carry potential prison terms of about 10 years , he said . The investigation began last year when the Civil Guard detected that two metal-forming `` dual use '' industrial machines had been illegally imported into Spain . The three Spanish suspects were administrators of the import firm , the captain said . Authorities later determined that the machines had been acquired from a company that works in the defense sector in the United Kingdom and had been brought to Spain with the aim of waiting for an opportune time to secretly send them to Iran , violating international sanctions against Iran for the development of its nuclear and missile programs . Authorities seized two metal-forming industrial machines , which could be used to make missile casings or equipment to aid in the enrichment of uranium , the captain said . The Civil Guard also seized abundant documentation about exports and the sale of defense and double-use equipment , as well as a large amount of computer data that is being studied , the statement said . In January 2013 , national police arrested two people in northern Spain and seized a trailer truck carrying 44 valves made of nickel and chromium alloy that were intended for export to be used for Iran 's nuclear program , the Interior Ministry said at the time . Spain suspends sale of riot gear to Venezuela .
Officials say technology could be used to make missile parts or enrich uranium . Sanctions prohibit export of certain machinery to Iran . Iranian , three Spaniards face charges and possible prison sentences .