Sticking to your Guns

I've seen a lot of forged signatures before, but one day, a student handed me the worst one I had ever seen.  It was in pencil and had been erased and retried several times, and even then, looked horrible.  I pulled a previous signature and compared it and found that it was not correct.  I confronted Herman about it, showing him real signature.  "My mom signed it this morning." He told me, "That's her signature." I told him that I was going to call his mom to confirm this.  "Go ahead." was his reply.  During prep that day, I called his mom to verify.  She had never seen the paper and had never signed it.  When I confronted him again, after the talk with his mom, he still said "My mom signed it.  I didn't sign it, it's her signature."  Even with his mom saying no, he still never gave in that he did it.