Complex sentence: At that time, construction workers bulldozed a section of land that tribal historic preservation officers had just documented as a historic, sacred site, and when protesters entered the area security workers used attack dogs, which bit at least five of the protesters.
Split into simpler sentences: At that time, construction workers bulldozed a section of land that tribal historic preservation officers had just documented as a historic, sacred site. When protesters entered the area, security workers used attack dogs, which bit at least five of the protesters.