Destroy gameobject by clicking it

I am working on a build and sell script for my towerdefence/castledefence and atm I am trying to make it so that when I click a tower(mouseposition), a GUI.button will appear and ask if I want to destroy this object and when clicked the tower will get destroyed.
Here is what I have got so far:

		if(Input.GetMouseButtonDown(0) && buildingTower == false){
			var hitDestroy : RaycastHit;
			if(Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), hitDestroy)){
				if(hitDestroy.collider.tag == "MiniTower"){ 
				wantToDestroyTower = true;
				if(wantToDestroyTower == true){
					if(GUI.Button(Rect(Screen.width/2 + Screen.width/3, Screen.height/2, 75,75),"Destroy")){
						var hitTarget = hitDestroy.gameObject;
						destroyTower = hitTarget.transform.root;
						wantToDestroyTower = false;

However when the gui button is clicked I get an error message saying it can’t find this gameobject. Field UnityEngine.RaycastHit.gameObject not found.
Thanks in advance!

RaycastHit does not contain a reference to a Game Object.