TAIPEI (Taiwan News) — Taichung’s fire department released a report on Friday confirming that a gas explosion caused a blast at the city’s Shin Kong Mistukoshi mall in February that killed five people and injured 38.

The fire department said that after 13 on-site inspections and discussions with experts, a panel unanimously concluded the event was a gas explosion, per PTS. It said investigators found evidence on the building’s 12th floor that included cigarette butts, wires, gas pipes, and powered disc cutters.

The fire department said the report has been handed to Taichung prosecutors and police for further investigation. Taichung City Government officials said Shin Kong Mitsukoshi submitted repair plans on Thursday, and the building now needs a safety assessment and other certifications before it can reopen.

The explosion ripped through the mall late morning on Feb. 13 as contractors worked on the 12th floor. Two visitors from Macau died on the first floor after being hit by falling debris, and their granddaughter died of her injuries earlier this month.

The blast also killed two mall workers who were found on the 11th and 12th floors. Reports of a gas explosion began to emerge shortly after the blast, and Taichung prosecutors are also investigating the cause.

The gas company supplying the mall said at the time there were no gas pipeline issues that could have led to the explosion. It added the mall’s gas pipelines had been sealed off days before.