The guard in charge of watching over cable cars on Mount Otake in Nagano Prefecture was briefly distracted by lost tourists when a fatal accident occurred Wednesday, according to police.
Police said Friday they are continuing to question employees of Ontake Ropeway, a joint public-private venture company that operates the cable car.
A 70-year-old man and his 62-year-old wife died after the cable detached from a pulley and they were thrown from their gondola.
Other passengers who were using the cable car at the time of the accident said there was no reply to emergency calls they made on the emergency wireless in their gondolas.
Nagano Prefectural Police and the transport ministry began investigations Thursday, surveying the area and studying the pulley and the cable.
Ontake Ropeway said the guard, who was in charge of watching a monitor located between the ropeway and the pylon near where the accident occurred, left his seat in the surveillance room on the mountainside for about a minute.
The guard, who was reportedly giving directions to passengers, returned to his post after hearing a strange noise.
He has reportedly said that the wind was calm and that when he looked at the wind gauge, the wind the blowing at 5 or 6 kph.
Tsutomu Tanimoto, an executive of Ontake Ropeway, has said: "Giving directions to passengers is also an important task. The wind was mild and there was no problem."
The company said one employee is based in the surveillance room and another works in the operations room at the foot of the mountain.