Additionally, investigators will want to know the context of the alleged assaults, and also whether the widely-circulated online video clips tell the whole story.
Pictures of the sign - which ends with a smiley face - have been widely circulated on social media, with many commentators congratulating the library on its stance.
El Pais, Spain's most widely circulated newspaper, cited unnamed anti-terror sources Wednesday as saying they believe there is a chance -- albeit small -- that Islamic terrorists would strike in Spain.
The entire film is thought to be around an hour long, although most have only seen a 14-minute trailer which has now been widely circulated on the internet in English and Arabic.
The Vancouver-based yoga gear maker's statement comes a day after a New York Post report that was widely circulated by the media recounted one woman's tale of being asked by sales staff to bend over to prove that the yoga pants she was trying to return were sheer.