Consequences after inviting someone on B2 visa and they did not return.

[tablenok]

Hi,
I have sent invitation letter to USA to my friend's friend. I met this guy one time. He got multiple 1 year visa at the embassy in February 2015
I just found out that he is planning to stay here illegally after his second visit to US.
He is currently in USA (arrived September 7th) but visa is not expired yet.

What are consequences to me as I have provided original invitation letter to US embassy.

Am I responsible for him?
Will I ever be able to provide invitation letter to anyone else? I need to send invitation letter for my brother's visit in December.

[kmm]

Hi,
I have sent invitation letter to USA to my friend's friend. I met this guy one time. He got multiple 1 year visa at the embassy in February 2015
I just found out that he is planning to stay here illegally after his second visit to US.
He is currently in USA (arrived September 7th) but visa is not expired yet.

What are consequences to me as I have provided original invitation letter to US embassy.

Am I responsible for him?
Will I ever be able to provide invitation letter to anyone else? I need to send invitation letter for my brother's visit in December.

Was it a letter on a plain paper or email?

[tablenok]

Was it a letter on a plain paper or email?

It was email invitation. Would it make a difference?