Here is the CNN interview of Huckabee defending his clemency decision. He admits to knowing how violent Clemmons was. Below the video are further written comments.
http://www.cnn.com/video/#/video/crime/2009/12/03/griffin.clemmons.huckabee.cnn
The prison record stated that Clemmons possessed a firearm at one time in prison. Huck admits in the interview that he reviewed all the files and still judged Clemmons worthy of clemency.