The incidents have been occurring at night usually between midnight and dawn, police detective Bill Lott said.
``We do believe that whoever is doing this is using some type of accelerant to get the port-a-johns burning rather quickly. They're all made of plastic, and once it goes up, it burns up rapidly, which is what we've seen in all the cases,'' Lott said.
No suspects had been identified or arrested as of Friday.
Police are planning to send remnants of one of the burned port-a-johns to the State Crime Laboratory in Jackson for testing to determine if accelerants were used to set them aflame.
Those responsible for the vandalism face arson charges and five to 20 years imprisonment if convicted.
``Our biggest concern is that if one of these port-a-johns is close to a house or other building under construction and is set on fire, then the fire could spread to the larger structure and possibly to an adjacent one that might be occupied,'' Lott said.
``We are urging people in areas where there is construction going on and port-a-johns have been placed to keep an eye out, especially at night. Being alert could help us catch those who are responsible.''
