The director of the board of trustees of Spain's Alhambra palace is under investigation for alleged embezzlement of public funds at the top tourist site.

Interior Ministry official Santiago Lopez said Alhambra director Maria del Mar Villafranca was detained Thursday and brought in for questioning. She was later released but remains under investigation.

Villafranca and four other board officials are suspected of misappropriating public money assigned for contracting visitor audio guide systems for the palace, which is located in the mountains on the outskirts of the southern city of Granada.

Considered a gem of Muslim architecture, the Alhambra is a UNESCO world heritage site and Spain's most-visited tourist attraction.