Gilbert Rodriguez Sierra was 19 when he was murdered near Gates Pass outside Tucson on November 2, 1973. Steelman, 28, and Douglas Gretzler, 22, forced Sierra into the trunk of his car after encountering them hitchhiking near the University of Arizona. He was driven to a remote spot and shot multiple times after being accused of being a police informant.

The killing of Sierra was one part of a broader killing spree attributed to Steelman and Gretzler that moved through Arizona and into California. The pair reportedly abducted a University of Arizona student the next day (who later escaped), and invaded a Tucson apartment where a young couple was murdered. Their crimes are said to have resulted in a total of 17 deaths; Steelman and Gretzler were later taken into custody in Stockton, California, and were convicted and sentenced to death.

If anyone knew Gilbert, saw him on or around November 2, 1973, or has information about his last movements, please share what is known.