Japan: Investigation resumes into deadly blaze

Police and fire officials are questioning witnesses and have examined the charred insides of a building for clues to what caused Japan's deadliest fire in more than two decades.

Fire officials say numerous safety violations prevented the victims from escaping and helped the fire spread from a staircase outside a mahjong parlour on the third floor to the bar above.

Investigators are focusing on a broken gas line near the third-floor stairway, as well as electrical wiring and other possible causes.

The fire raged through a four-story building in the nation's biggest entertainment district, killing 44 people and injuring three others.

Police are questioning witnesses and shopowners around the building and have not ruled out the possibility of arson.

Mourners left bouquets of flowers, bottles of sake and other tokens of their grief before the building's entrance.

Packed with bars, adult night clubs and gambling parlours, Kabukicho is notorious for the large numbers of drunken people staggering along its neon-lit streets at night. It is also known as a hotbed of organised crime.

The fire was the worst in Japan since 1980, when 45 people were killed in a burning resort hotel in northeastern Japan.

Fire and police officials say the building had previously been cited for fire code violations.