Five people were found dead Friday evening in a private residence in the eastern Tokyo ward of Edogawa in a suspected group suicide, police said.
The bodies of one man, three women and one person of unknown gender were found at around 9 p.m. in a room on the second floor of the residence, they said.
The five were lying in a closed room where charcoal had apparently been burned. The house entrance was locked and the window of the room was sealed with packing tape, they said.
A 37-year-old man who lived in the residence is currently unaccounted for. The man communicated with a Twitter friend around Tuesday, mentioning his desire to die and a gathering of people wanting to commit suicide.
The friend informed the police about the man on Friday, resulting in the discovery of the five people. The police believe that he is among them.