A man found a body Sunday evening in the Atsugi, Kanagawa Prefecture, apartment of his brother after the landlord alerted him that the rent had not been paid.
The Kanagawa Prefectural Police said the brother, 58, and his wife, who was described as being in her 70s, are considered missing.
The police said they had yet to identify the corpse or determine the gender.
They opened an investigation on suspicion of abandonment of a body.
The body was reportedly wrapped in a sheet formed by taping together multiple translucent plastic bags. It was found lying on a sheet spread on a tatami-mat floor.
The older brother, 61, visited the apartment and opened the locked front door with a spare key borrowed from the landlord, who had earlier notified him that the younger brother failed to transfer the rent to a bank account. The payment was due Dec. 16.
The younger brother’s car was also missing, the police said.
The apartment is located about 1.5 km northwest of Atsugi Station on the Odakyu Line.
“I sometimes saw the couple go out together in their car,” a housewife in her 50s who lives nearby said. “Their car was usually parked in a parking lot in front of their apartment, but I didn’t see it parked there recently.”