Sorry, but "they could only view his head and neck - the rest of the body was covered in plastic" point pretty much invalidated the "They have seen his body. There was NO WOUND whatsoever on his wrists" claim.

As for witnesses, I refer u to what reporter Zul Othman wote in TODAY newspaper, 03 March 2009:

A contractor who was possibly the last to see the undergraduate alive told Today he was in the building when he saw a bloody trail leading from the office entrance, and Mr Widjaja, dressed in a beige T-shirt and shorts, sitting on the parapet.

Said the man, who wanted to be known only as Mr Tuen, 56: “There was a lot of blood where he was sitting because his wrist was bleeding. I panicked and asked him what he was doing, but he looked dazed and kept quiet.”The contractor rushed into the office to get help, but when he returned, the student was lying at the foot of the block.

And I suppose your claim would be if TODAY paper reported it, hence it must be true.