A former general manager of the Grand Hyatt Tokyo is facing arrest over his suspected sexual assault on a female customer in a bathroom at the upscale hotel in central Tokyo in May, police sources said Tuesday.

But Antonio Alvarez, a 45-year-old Spaniard who assumed the top post last December, left Japan in early August after quitting the hotel in the upscale Roppongi district. The Metropolitan Police Department has obtained an arrest warrant and will take him into custody if he re-enters Japan, the sources said.

Alvarez is suspected of forcibly taking a female customer in her 20s into a multipurpose bathroom at the hotel at around noon on May 30, kissing her and forcing her to touch the lower half of his body, the sources said.

An aquaintance of the woman later called police and Alvarez visited the MPD's Azabu Police Station, where he denied the allegation. But a police DNA analysis of substances found on the woman confirmed that he sexually assaulted her, the sources said.

The Grand Hyatt Tokyo has offered an apology and vowed to cooperate with the investigation.