Richmond relied on declassified federal government documents and various long-forgotten El Paso archives for his research, including meticulous case notes and files compiled by Chris Fox, the El Paso County sheriff who pursued the case relentlessly.Richmond is convinced that Fox, who emerged as one of El Paso’s most prominent citizens, probably came closer than anyone else to solving the case even after the Texas Rangers took over the investigation. The book contends petty jurisdictional jealousies among various law enforcement agencies hampered the investigation.