Maria Remedios Garcia Albert is said to have worked for an NGO
Spanish police say they have arrested the representative of the left-wing Colombian rebel group Farc in Spain.
Maria Remedios Garcia Albert, a Spanish national, was detained near Madrid, as part of a joint operation by the Spanish and Colombian authorities.
She faces charges of being part of an armed group and managing the rebel group's finances in Europe.
Farc, which has waged a 44-year civil war in Colombia, is considered a terrorist group by the EU and the US.
The Colombian authorities have recently warned that large amounts of money raised from cocaine by the Revolutionary Armed Forces of Colombia - or Farc - are often invested in Europe.
The BBC's Steve Kingstone in Madrid says it is alleged that under the cover of her job with a non-governmental organisation, Ms Garcia provided organisational support and funds to the Farc.
In a statement, the Spanish police said Ms Garcia had travelled to Colombia last year - and held operational meetings with the militant group's secretariat.
She is said to have taken direct orders from Raul Reyes - a senior Farc commander who was killed by the Colombian army in March. Information from his computer hard drive is said to have led the police to make this arrest.
At the suspect's home in San Lorenzo del Escorial, north west of Madrid, officers recovered a computer and documents, allegedly referring to the Farc.
It is claimed that Ms Garcia helped co-ordinate the group's wider activities in Europe - allegedly liaising with counterparts in Switzerland and Sweden.