Naomi Roht-Arriaza has published an article chronicling efforts to prosecute leaders of the deposed Guatemalan regime for genocide and torture, among other things, with the help of Spanish legal process. The article is titled, "Making the State Do Justice: Transnational Prosecutions and International Support for Criminal Investigations in Post-Conflict Guatemala," 9 Chi. J. Int'l L. 79 (Summer 2008).
Naomi has also co-authored a chapter on Guatemala in a book called Victims Unsilenced, published in 2007 by the Due Process of Law Foundation. (It's in Spanish.) Here's the link: http://www.dplf.org/uploads/1202485080.pdf.