An elderly man in western Japan has died after he was bitten by a Tosa Inu dog that he was looking after for an acquaintance, police said Monday.

Tsutomu Fukumoto, 82, was found dead with wounds on his back, along with the adult dog, inside a kennel near his home in Minamiawaji, Hyogo Prefecture, after emergency services received a call from his 55-year-old son around 8:40 p.m. on Sunday, reporting his father had been bitten by a Tosa Inu.

According to police, Fukumoto was taking care of his grandchild's three Tosa Inu, as well as the one for the acquaintance, which is believed to have attacked him while he was tending it.

(File photo of a Tosa Inu dog)

The four dogs were kept separately in iron cages, each measuring 2.6 meters long by 1.3 meters wide, with a height of 1.4 meters. The doghouse contains seven such cages.

Fukumoto was found collapsed in the cage by his 75-year-old wife, who went to check on why he had not returned after leaving their house, about 200 meters away, around 5 p.m. All other dogs were in their respective cages.

Citizens are required to register their dogs under the rabies prevention law. However, there was no notification that Tosa Inu were being kept there, local officials said.

Tosa Inu, also known as Japanese mastiffs, originate in the Tosa Province, now Kochi Prefecture, on the island of Shikoku, where it was bred to be a fighting dog. Owners of such dogs require a license in a number of countries.