An investigation into a forest fire that killed 30 people in south-western China last month found the blaze was caused by lightning, state media reported late Friday.  
The fire broke out on March 30 on a 3,700-metre mountain top in China's south-western Sichuan province after lightning struck an 18-metre pine tree, news agency Xinhua reported citing local authorities. 
The tree was apparently torn apart by the lightning and set the nearby area ablaze as it fell to the ground. 
More than 600 people were called to the scene to help put out the fire. Twenty-seven firefighters and three local residents were killed.