Investigators examining the deadly fire that ripped through two neighboring low-rent hostels in Kawasaki, Kanagawa Prefecture, have found that they lacked fire proofing.

At least eight people were killed in the fire early Sunday, and 19 others were rushed to the hospital, police and firefighters said.

Kawasaki City Hall said the Yoshidaya hostel, where the fire broke out, appears to have extended its original wooden building illegally. The Buildings Standards Law requires that a building of that type be demolished and replaced.