Quote Originally Posted by AdrianII
The wounds have to be explained. The nature of the burns in combination with the intact clothes strongly suggests the use of a chemical as the killer.
Not at all - chemical agents that are used in munitions do not leave burns - it leaves blisters or nerves completely shut down - in other words the cause of death is very obvious. Now Blood agents are a little harder to detect - but if one knows what to look for - the cause of death can be determined.

Burns mean that the weapon used was a phyrotechnic of some type - either fuel air explosive or intense heat created by smoke.

Because once it has been allowed to burn out, phosphorus disappears. It says so in the link you provided: 'White phosphorus burns spontaneously in air. These weapons are particularly nasty because white phosphorus continues to burn until it disappears.'

And now you know in your own words why it is not considered a chemical weapon. But a smoke or pyrotechnics.