Who logged these logs in Sarawak?

There is a huge environmental disaster unfolding in Sarawak. 

Heavy rains flooding a logging camp in the interior of the state has forced millions of cut logs and wood debris into the Balleh river. The Balleh river joins into the Rajang river which flows past Sibu before emptying into the South China Sea. Right now, the Rajang is a river of sludge -- a mixture of logs, debris and mud.

There should be no pity for the people behind this ecological disaster of unknown proportions. All the destruction, all the waste. Questions must be asked of the authorities.

Who is behind this logging? Why is there such an extensive logging? In the first place, is this logging legal or illegal? If legal, who approved the logging licences? Who is going to take even a wee bit of responsibility over the destruction of the environment over there? Will we ever know the answers?

The above picture is from Hornbill Unleashed. More photos are available there.