Police and the British Embassy are seeking a 40-year-old British CEO who vanished in Tokyo more than a week ago.
Garin Dart, a Tokyo resident and founder of the event management company Bluesilver, was last seen May 22 heading to a meeting at a Shinjuku hotel.
"He literally vanished," Bruno Dammizio, a director at Blusesilver, told The Japan Times on Friday.
Dammizio said the disappearance was uncharacteristic of his colleague, whom he described as "a hardworking individual," especially since it was a busy time for the company.
Dart's wife, Yukako, reported him missing.
The authorities have reportedly found no irregular activity regarding his bank account or credit cards, and he hasn't been admitted to any hospital.
Dammizio said he hasn't contacted any Japanese media for aid and is letting the embassy and the police do their job for now.
"We have been in regular contact with his wife and the police," he said. "We are very much concerned."
The case has received wide coverage in the U.K., including on the websites of the Independent, Guardian and Daily Telegraph newspapers.
In addition to his business, the London native is involved in a group called Foreign Volunteers Japan. He cofounded the organization following the March 2011 earthquake and tsunami.
According to the Foreign Volunteers Japan website, Dart has lived in Japan for about a decade and his wife is pregnant with their second child.
"After a decade of successful projects, the gradual expansion of his company, a loving family and many close friends and colleagues, it seems unlikely that he would just disappear by his own will," a statement on the website says.