Roadside crash barriers, storm-drain covers, heavy factory doors, as well as mining equipment, irrigation machinery and even cemetery planters made of metal have all gone missing in and around Thessaloniki, the country's second largest city, amid concerns that previously law-abiding Greeks are turning to crime in growing numbers.In northern Greece, rogue merchants have an additional advantage: A 1,228-kilometer (763-mile) border with four countries that makes it easier for them to dodge stepped-up police checks on local scrap yards. Police near the frontier with Turkey last month arrested 18- and 19-year-old suspects accused for stripping 300 meters (nearly 1,000 feet) of cable from street lights, blacking out a stretch of newly built highway that runs across northern Greece. Recent inspections also turned up another 300 meters of stolen cable on a passenger bus headed to Albania, along with a cache of candle holders, snatched from graveyards and loaded onto small trucks, that were stopped and searched at the Greek-Bulgarian border. Police inspections for stolen metal have now become a priority at the country's 12 main border crossing points. "We've had (metal) theft in the past, but there's been a spike in the number of cases recently, with a greater number of criminal gangs involved," Antonis Tzitzis, head of Thessaloniki police's department for crimes against property, said in an interview. "Before the crisis, we had very few cases of metal theft. Now they are multiplying exponentially," he said. "Our indications are that many Greeks currently accused of involvement in metal theft had no previous criminal involvement." A disused army-built rail bridge network in northern Greece and its 500-kilogram (1,100-pound) steel girders has become a favorite site for thieves. The bridges have been targeted on at least three occasions, in one case leading to the arrest late last year of a 36-year-old man and two women, aged 36 and 40, as they were removing a bridge support, 40 kilometers (25 miles) west of Thessaloniki.