City streets are getting darker because thieves, some disguised as utility crews, are stealing 30-foot light poles, authorities said.

About 130 aluminum light poles have vanished this fall from locations across the city, despite the difficulty of carting off the 250-pound objects.

The culprits have even dressed up as utility crews, city officials say, and placed orange traffic cones around the poles they are about to take down to avoid making motorists suspicious. Police have no suspects in the thefts, first reported in the Baltimore Sun.

Police say the thieves could be stealing the poles, which cost the city $750 each, to sell as scrap metal. For at least a decade, authorities suspect drug addicts have ripped metal pipes, radiators and wires out of vacant houses to pay for their next fix.

Scrap aluminum brings 30 to 35 cents a pound, according to local metal dealers.