A worker at Japan's Tokyo Station got an unpleasant shock after opening an abandoned suitcase that no one had claimed for a month -- the decomposing body of an elderly woman inside.

The Tokyo Metropolitan Police said the corpse was found Sunday in a suitcase in a temporary storage area at Tokyo's main train station. Japanese media reports said the body was of an elderly woman who stood 4-feet, 7-inches tall. Police are trying to establish her identity.

The bright yellow suitcase was left in an unlocked coin locker on April 26, according to the media reports. It measured 28 by 20 by 10 inches.

Nothing unusual was observed about the suitcase, no odor or anything, said Junichi Omoto, a spokesman for regional train company JR East.

"We were surprised and horrified," he said.

It's normal practice to hold abandoned luggage for a month to see if anyone claims it.

Major Japanese train stations have banks of lockers for travelers to store items temporarily.