U.S. Teacher Killed 'With a Sharp Tool' in Abu Dhabi Shopping Mall

(NBC) An American kindergarten teacher who is the mother of twins was stabbed to death in the bathroom of an Abu Dhabi shopping mall by a robed figure dubbed the "Reem Island Ghost," police said Wednesday.

The attack comes just weeks after the U.S. embassies in the Middle East warned citizens of an anonymous posting on a jihadist website encouraging attacks against teachers at American schools in the Middle East.

The U.S. Embassy in Abu Dhabi confirmed an American citizen was killed Monday in a public restroom at a shopping mall on Reem Island and said it is working with "all appropriate authorities" to seek further information.

"There is no information available at this time about the nature of the crime," it added in a statement. No further details were provided.

Abu Dhabi police said that the 37-year-old woman reportedly was attacked "with a sharp tool" following a fight in the public restroom on Monday, with witnesses saying the suspect was cloaked in a traditional black robe, gloves and face cover.

"The injured woman was immediately rushed to Sheikh Khalifa Medical City where she succumbed to the wounds she sustained in the attack," Abu Dhabi police said in a statement, adding that the suspect had immediately fled the scene after the attack. Police said an investigation is underway into the cause of the fight and the suspect's motive, identity and gender.

Col. Dr. Rashid Mohammad Borshid, head of Abu Dhabi's Criminal Investigation Department said that police are now caring for the victim's twins.

In a surveillance video released by Abu Dhabi police, the suspect is shown exiting an elevator and appearing to have a quick interaction with a mall security officer — before grabbing a newspaper and heading into the bathroom.

According to the timestamp on the video, the suspect hustles out of the bathroom around 90 minutes later and heads straight for the elevator as bystanders scatter. At the elevator door, a female bystander apparently tries to stop the suspect but quickly retreats. The suspect then dashes into the elevator — and other bystanders soon rush after.

Police said they have not determined the gender of the assailant.

On Oct. 29, the U.S. embassy in Abu Dhabi issued a warning to U.S. citizens about the anonymous posting encouraging attacks against American teachers, but said it was "unaware of any specific, credible threat against any American or other school or individual in the United Arab Emirates."

"Nonetheless, the Mission is working with local schools identified with the United States to review their security posture," it said. "U.S. citizens residing in or visiting the UAE should remain vigilant regarding their personal security."