According to a Spanish Interior Ministry statement, Villota, who is originally from Bilbao, has lived with false documents in the UK and has been "waiting for instructions" from Eta.
The Ministry says Villota was recruited in 1990 to join the legal Matalaz Command, under the Command Vizcaya.
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Wintry flurries overnight for West Lancashire, Cumbria and North Wales. Icy stretches developing by morning. Windy and feeling bitterly cold
Christie Newport says a rare illness which swells her face and body has ruined her life.
We are into the longest cold spell of winter so far. More wintry flurries and bitterly cold weather to come