In construction site theft normally occur when subcon are not paid

The subcon usually hold their worker wage if no payment then the worker will steal materials and equipment to recoup their loss wages

Stealing from construction site require some insider cooperation, normal drug addicted mat pet won't be able to do it

Yes mat pet will do that, cut big cable and died

But they won't know what equipment is valuable what is not inside a service box, only insider know that, also they won't know the path on the construction site which route to take. They also won't know how to pass security gate using vehicle, won't know how to hire lorry or 4wD to get inside the site carry those stolen equipment.

Mat pet only knows how to cut copper cable and carry it with motorcycle, everything else they don't know.

This very likely the work of insider