Four men were found dead early Sunday inside a Tokyo apartment, apparently after carrying out a suicide pact, police said.
Meanwhile, police in Gunma Prefecture found the bodies of a man and two women in a car parked in the woods of the town of Minakami in the afternoon and were investigating the case as a group suicide.
Investigators in the Tokyo case said the bodies had no external wounds, and four small stoves containing burned charcoal were found in the room with them. The 4 1/2-tatami mat room was sealed from the inside with adhesive tape.