A 46-year-old man was found dead in a suitcase along the Tama River in Kawasaki, police said Saturday night, treating it as a murder case.
An autopsy showed that the man, identified as Tadayuki Hara, whose address and employment status is unknown, died of suffocation. He appeared to have died a few days prior to the discovery.
Kanagawa police said Hara was found in a large suitcase with his arms and legs bent.
A person who was fishing along the river found the suitcase in a muddy area and called the police at around 10:10 p.m. on Friday.
Investigators suspect Hara was killed somewhere else, placed in a suitcase and dumped near the river, NHK reported.
There are houses and factories near the site where the suitcase was discovered, with Tokyo's Haneda Airport located across the river.