Mexican authorities said that they've found the bodies of 167 people in a southern Mexican cave, and forensic experts believe the remains are at least 50 years old, according to AP. Prosecutors in Chiapas state said in a statement Saturday that the remains were found Friday on the Nuevo Ojo de Agua ranch in an area frequently used by Central American migrants traveling north. The statement said there were no visible signs of violence on the remains, which "break easily." The authorities say they will "not discard any line of investigation." Mass graves have been found in the past two years mainly in northern Mexico containing the bodies of dozens of migrants and others allegedly killed by drug cartels.