Reporting private messages?

[Hawk]

Hi there,

I am sorry if this is posted in the wrong place or there is a very easy way of doing this, but how can I make it so users can report private messages?

I remember there being a plugin for myBB 1.2, is there one available for 1.4? Or is there a setting that I can turn on to make it so users can report private messages?

Thanks very much for your help in advance.