Copy admin in to messages sent via the contact form

Hi.
Im hoping someone can help.
I need top add functionality so that admin receieves a copy of any messages sent via the contact form.
My website is for quite a niche market and i think someone is currently abusing the messaging system to send messages to canvas for their own business. Ie – messages sent one after another to many of my listing owners, this is very unusual as my contact form normally only gets used 2-3 times a day!
It would be handy to be able to see what messages are getting sent.
Hopefully someone can help.
Thanks in advance