The fire broke out Sunday and was reportedly cause by farmers burning sugar cane fields near the ancient site.The Ventarrón archaeological complex was discovered in 2007 and housed a 4,500-year-old temple with a variety of preserved pottery and art. The mural was carbon dated to 2000 BC — thousands of years before the Inca civilization.The site is located in the Lambayeque region, about 475 miles north of Lima. "We have lost the cradle of our culture," said Ignacio Alva Meneses, director of the Ventarrón Archaeological Project. "Five thousand years of history, the original temple, the origin of the Northern Peru civilization, mural art and the oldest and most complex symbolic meanings destroyed in a few hours." A collection of human remains excavated at the time of the discovery was also damaged in the fire, according to Peru's state media Andina. The fire reportedly consumed the roof of the complex, melting plastic covers and engulfing the ancient site in a thick black smoke."The losses are irreparable." Director Meneses said.The Peruvian Ministry of Culture announced an official investigation to determine who was responsible for the fire.