Can anybody tell me how can I delete the related documents?

I'm using the following code but it is not deleting the related documents.

Document
 
 
 originalDocument = new Document(sender.Id);
 
 
if (originalDocument.Relations.Length > 0)
{
 
 
foreach (Relation r in originalDocument.Relations)
{
 
 
Document doc = new Document(r.Child.Id);
doc.delete(
 
true);
r.Delete();
umbraco.
 
library.RefreshContent();
}
}