Police have found a bloodstained sweat-shirt in the home of a family of four discovered slain Sunday morning in Tokyo’s Setagaya Ward, investigation sources said Wednesday.
Police believe the shirt belonged to the assailant and released a photo to the press appealing for information from the public.
The sources also said the family of Mikio Miyazawa, a company employee, may have been killed by a single assailant. Police earlier indicated that more than one attacker was thought to have been involved.
The sweat-shirt was found inside out on the second floor of Miyazawa’s house, with bloodstains on the front and the sleeves. The body of the shirt is white and it has violet sleeves.
Miyazawa, 44, his wife, Yasuko, 41, their 8-year-old daughter, Niina, and 6-year-old son, Rei, were found dead in their home in the Soshigaya area of Setagaya Ward. The first three were apparently stabbed to death and the boy strangled. The attack is believed to have occurred around 11:30 p.m. Saturday, as a neighbor has reported hearing a loud noise from the house around that time.
The wife and the two children were clad in what appears to be nightclothes. Miyazawa was wearing regular clothes.
A witness who passed by the house around 6:30 p.m. Saturday said Miyazawa’s car was gone, according to police.
Police now suspect that the assailant or assailants broke into Miyazawa’s house when he was away, killed the wife and children, and then murdered Miyazawa upon his return.
The inside of the house had been ransacked when police first arrived at the scene, leading investigators to believe that more than one person was involved in the murders.
Police later said they were searching for three unidentified men who left bloodstains in a taxi they hailed Saturday near the house.
However, the only footprints found so far at the scene that did not belong to any of the family members appeared to be those of a single person. Investigators now say it is possible that only one assailant was involved, the sources said.
A large quantity of blood that did not match the types of any of the victims has been found at the scene. Police believe that the assailant, or one of the assailants, may have been wounded by his own weapon during the attack.
Police believe the sweat-shirt found on the second floor belonged to the assailant because it was too large for Miyazawa and it sustained no cuts, even though the victim suffered more than 10 stab wounds to his upper body.
Investigators have determined that a Japanese clothing retailer imported about 2,200 of the sweat-shirts from China and started selling them in Japan in September. Between 200 and 300 of them are known to have been sold in Setagaya and surrounding areas.
Police currently suspect burglary as the chief motive behind the murder because there are signs that cash had been taken from more than one of Miyazawa’s purses kept in the home, although his bank cards and deposit certificates were left behind.