Why cement companies? A theory. Cement rotary kilns, often hundreds of feet long, at large cement plants burn input material (such as crushed limestone) at approximately 2600 Degrees F. That would be a good place to dispose of crime evidence. If networks of trains, trucks, local concrete batch plants are used for human trafficking transportation, and this is Murder Inc., then a large cement plant (where Portland Cement is made) could be used to incinerate all evidence of murder/mass murder including input of dead bodies into the cement kiln which would incinerate virtually everything at those high temperatures - making everything into cement product which is then sold to unwitting consumers.