The word أشلاء is the plural of شلو, which is a dismembered or mangled part of a body that has been killed in a brutal way, as in the famous poem, "The Eagle," by Omar Abu Risha:

واطـرحي الكبرياء شلوا مدمى
تحت أقدام دهرك السكير

And later in the same poem:
وقف النسر جائعاً يتلوى
فوق شلوٍ على الرمال نثير

However, the proper translation of الأشلاء in the context of this passage depends on how you choose to translate the preceding word الخراب, because الخراب والأشلاء is one unit.

If you choose to translate الخراب to "mayhem" or "destruction," then الأشلاء should be translated "death."

وتترك خلفها الخراب والأشلاء
". . . leaving behind mayhem (or destruction) and death . . ."

This option gives more weight to the moral import of the marauding action being described than to the concrete imagery. It is not bad, but it is not very faithful to the source text.

If, on the other hand, you prefer to be faithful to the concrete imagery, then you should try something like:

وتترك خلفها الخراب والأشلاء
". . . leaving behind ruins and dismembered bodies . . ."

The language here is more concrete and more picturesque.