NAHA, OKINAWA PREF.

The cause of the fire that devastated Shuri Castle, a UNESCO World Heritage site in the southernmost Japan prefecture of Okinawa, has yet to be identified, one month after the tragedy shocked people at home and abroad.

Although fire authorities increasingly suspect that the blaze was triggered by an electrical system glitch, it is difficult to determine the cause of the fire as the site was almost fully burned down, an official in the authorities said.

The authorities plan to release an investigation report by the end of this year at the earliest, but it may not identify the cause of the fire, informed sources said.

The fire occurred in the wee hours of Oct. 31, damaging seven buildings at Shuri Castle, an Okinawa symbol, including the "Seiden" main hall.

On-site inspections by the Okinawa prefectural police department and local fire authorities have found burned and melted parts on an extension cord connecting indoor lighting equipment to a switchboard at the north side of Seiden.

There was also a melted part on a wire that sends electricity to the switchboard from outside Seiden.

As the switchboard was badly burned into the inside, local fire authorities were unable to identify whether the burning and melting occurred due to short circuit or secondary damage from outside fire, according to the authorities.

"We are using microscopes" to analyze carbonized items collected from the fire site, a senior official of the prefectural police department said.

With no signs of a suspicious individual at the site, the fire authorities increasing believe that the blaze was caused by an electrical system glitch, the sources said.

Jiji Press