Generally speaking what you described is called ex post facto and is considered a violation of our society if it impacts a crime committed in 1980. I.e., if it was not a crime in 1980, and it is now a crime in 2007, it won't apply to you.  However, if it was a crime in 1980, your question is not the issue.  The issue would be statute of limitations to bring forth the criminal claim (i.e., there is never a bar to bring forth a case of murder).