Takehiko Kimura, deputy mayor of the city of Chigasaki, Japan, was found unresponsive in waters off of Waikiki on Saturday morning, KHON reports. He was taken to the hospital where he was later pronounced dead.

Kimura had traveled to Honolulu to join Mayor Kirk Caldwell and Council Chair Ernie Martin for a sister signing ceremony, which was held Friday at Mission Memorial Auditorium, according to the mayor’s office.

“We were shocked and saddened to learn of the loss of Deputy Mayor Kimura on Saturday morning,” Caldwell said in a statement.

Kimura’s death was confirmed on Tuesday by the medical examiner’s office. The cause of death was not disclosed.