Complex sentence: Because many of these people were fugitives and others had died in the clash, the penalty could only be applied to 42 detainees, who were led to the citadel of Chan Chan, and were forced to dig trenches that would become their graves.
Split into simpler sentences: Because many of these people were fugitives and others had died in the clash, the penalty could only be applied to 42 detainees. They were led to the citadel of Chan Chan, and were forced to dig trenches that would become their graves.