Vermont State Police are investigating the theft of copper grounding cable taken from three Green Mountain Power substations.

Officials at Green Mountain Power say that copper thefts at sub-stations are threatening the lives of utility workers and the public.

In Middlebury, authorities are looking into a copper theft from a construction site over the weekend. The incident comes as the state of Vermont is seeing a rash of copper thefts.

Vermont State Police hope to crack down on the thefts of copper, catalytic converters and other scrap metal by enforcing laws on salvage yards that buy them.