Complex sentence: Arizona police were not able to name a murder suspect, but traced a set of footprints from the crime scene south towards the border, and the resulting speculation that the killer was an illegal alien increased support among the public for the measure.
Split into simpler sentences: Arizona police were not able to name a murder suspect but traced a set of footprints from the crime scene south towards the border. The resulting speculation that the killer was an illegal alien increased support among the public for the measure.