|This question is not only asked among Spanish students, but also among Spanish speakers! In fact, we, Spanish speakers don't have clear ideas about which form we should use. |
I think it would be a good idea to let you know what's the right form. Whenever we use the form "Detrás de (someone)", the wrong expression is using "detrás" followed by the corresponding possessive pronoun. Let's see some examples to clarify this:
Hope this helps!