Police have arrested a couple on suspicion of directing four teenagers in a home invasion robbery-murder in Tochigi Prefecture.

According to police, the 28-year-old man and his 25-year-old wife, who live in Yokohama, conspired with others in a plan to break into a house in the town of Kaminokawa on May 14 with the intent to rob.

While the executors were searching for valuables, they are alleged to have stabbed a 69-year-old female resident fatally and injured her two sons.

The male suspect was arrested at the international terminal of Haneda Airport in Tokyo. He is believed to have been attempting to flee overseas.

Investigators found the female suspect at a hotel in Yokohama along with her 7-month-old daughter and later arrested her.

In addition to the couple, four 16-year-old boys from Kanagawa Prefecture have been arrested as suspected perpetrators.

Investigative sources said that the pair may have provided the luxury foreign car used in the crime. One of the teenagers is believed to have driven the vehicle.

Neighbors said they saw a car similar to the one used in the crime frequently parked near the suspects' apartment in Yokohama.

Some of the teenagers have told police that the couple asked them to carry out the robbery.

Police are continuing their investigation, considering the possibility that there may be higher-level figures directing the operation as part of a loosely organized crime ring in which participants are not fixed and do not know each other's real identities.