Problem change materials

Hello guys , I have a problem to change a material of childrens of my father game object , my script find correctly the childrens that i want to change material, but don’t work anything and materials don’t change.

Here’s the script

public void ChangeBody(GameObject Vittim)
		Transform tr2 = Vittim.transform.GetChild(3);

		Transform tr3 = tr2.GetChild(1);
		Transform tr4 = tr2.GetChild(2);
		Transform tr5 = tr2.GetChild(3);


		tr3.gameObject.renderer.material = MatBody**;**

__ tr4.gameObject.renderer.material = MatBody**;__
__ tr5.gameObject.renderer.material = MatBody;**__

** }**
the game object that i want change the material at level editor is this

i use the unity version 4.3.2f1

You can try this

var materials : Material[]; //Select the materials here

renderer.sharedMaterial = materials[0]; //You call this to change the material