Selangor police chief Hussein Omar Khan added that police investigations into elements of negligence or mischief in the incident are ongoing.

“(Excavation at the blast site) is nearly done and we have already found the pipe that exploded.

“Studies are being conducted by forensic police, the occupational safety and health department, as well as fire and rescue department.

“So wait for another week. We will be issuing a preliminary report on our findings,” he said at a press conference here.

The blaze involving one of three natural gas pipelines broke out at about 8.10am on April 1, sending flames more than 30m into the sky, with temperatures soaring to 1,000 degrees Celsius.

It took nearly eight hours for the fire to be extinguished. The blast left a crater 8m deep and 70m wide. As a result, 111 victims required medical treatment for burns and breathing difficulties.

The fire also left 81 houses destroyed, another 81 houses partially destroyed, and 57 damaged but not burnt.