I have already delete the item from the scene before deleting. Also there is no event or signal which is accepting item as parameter where i am deleting the item.

The application has a graph like structure, so deleting a node also results in deletion of an edge. so removing both the items from the scene I instantiate its deletion.
Also the problem is not reproducible every time. Only for a specific node, at a specific position and graph layout this problem occurs.
To give you an idea deleting a node result in following process:
1. Find the boundingRect() of the node and check the intersecting items for the bounding rect of type edge.
2. Check if the egde is really connected to the node.
3. If yes, remove the edge from the scene and instantiate deletion of the edge and the node from the graph.