YOKOSUKA NAVAL BASE, Japan — Japanese police are working with the U.S. Navy to find the man who punched a 60-year-old taxi driver in the face Sunday morning in Yokohama.

Police reports stated that the suspect was in the company of two Yokosuka Naval Base sailors earlier that morning, but the two sailors said they’d just met him and could not identify him.

A concerned citizen called police at about 6:20 a.m. to report an argument between a non-Japanese person and a taxi driver outside the Yokohama train station, a Tobe police officer said Tuesday.

They were arguing about the 1,780-yen (about $15) taxi fare and the man punched the driver in the face, the police officer said. The driver suffered facial bruising that will take a week or two to heal, the policeman said.

The man was among a group of five non-Japanese people who took two cabs from Bay Hall in Shin-Yamashita area to the train station’s east exit, the policeman said.

Three got in one taxi and two — the Yokosuka sailors — got in the other cab. The Kanagawa Shimbun newspaper reported that a woman was with the larger group, but police would not confirm that.

Someone in the group paid the fare after seeing the man and the taxi driver arguing, he said, adding that police questioned the Yokosuka sailors, who told them they’d just met the men.

The Tobe police officer said all accounts are “conflicting and vague” and the matter remains under investigation. Police are working with the Navy to find the assailant, he said.