KIEV, Ukraine -- Let this be a lesson to anyone looking to join an insurgency abroad: Don't post photos of yourselves posing with military equipment on social media when you return home.
That's how police identified eight suspects who they
Police said the suspects belonged to communist organizations and had received support from an unofficial pro-Russian network in Europe.
People from around the world have reportedly traveled to Ukraine to take part in the fighting on both sides of the conflict, raising the question of whether they would pose a threat to their home countries when they return.
The three men returned to Spain earlier this month and were arrested Friday. Officials said they identified the suspects thanks to their habit of posting photos of themselves with military equipment on social media.
Spanish police released two videos showing the arrests of two of the suspects. Inside one man's apartment they discovered several hand guns, a high-powered rifle with a scope and Russian military paraphernalia as well as a patch used by pro-Russian rebels.
While police did not disclose the identities of the suspects, photographs released by authorities appeared to show two Spanish fighters interviewed by journalists in August.
Reuters spoke to Angel Davilla-Rivas, who told the news agency he arrived in Ukraine by train from Madrid with another man named Rafael Munez Perez. After arriving in eastern Ukraine, the two men joined the Vostok battalion, one of the most prominent and heavily armed factions.
According to Spain's El Pais newspaper, the 27-year-old Perez, 27, is a former social worker from Madrid active in communist politics. The paper said that the other man, 22-year-old Davilla-Rivas, is from Murcia and a youth member of the Spanish Communist Party.
Davilla-Rivas and Perez also gave an interview to the Russian outlet RT in August in which Davilla-Rivas expresses his disgust with Kiev.
"They are sending mercenaries to kill journalists," he said, seated with Perez in front of a red Communist flag.
A second video published the same day shows the two Spaniards brandishing Kalashnikov rifles and taking target practice at what appears to be a shooting range on the Vostok battalion base near Donetsk.
Davilla-Rivas is seen wearing a camouflage military cap adorned with a pin of the red Soviet star and golden hammer and sickle. At one point in the video, Davilla-Rivas removes his shirt and lifts his arms to reveal tattoos of Soviet leaders Vladimir Lenin and Josef Stalin on the sides of his torso.
The alleged fighters from Spain, detained during raids in six regions across the country, face charges of complicity in murder, possession of weapons and violating Spain's international interests. The 11-month-long conflict has killed more than 5,800 people, the United Nations estimates, although it said the actual number could be much higher.