They've robbed graves and construction sites, churches and schools. They've taken downspouts, statues from bases and ordinary pipes right out of the walls.
Even a new state law designed to curb these scrap metal thieves seems to barely slow them down.
Copper theft, striking many utilities and other businesses, has been common in Maryland since sharp price increases took the price of copper from about $1.25 per pound in January 2009 to about $4.50 per pound in May 2011.
Copper theft reports routinely show up on the Nothern District's weekly crime logs, and were identified as a major problem in Wyman Park Dell and other Baltimore City parks last year, leading the Department of Recreation and Parks to take expensive steps to combat the thefts.
In the dell, thieves kept stealing underground copper wiring that runs between the light poles, rendering the dell dark at night and leading many residents to conclude it was unsafe at night..
The department said it was spending an estimated $100,000 to make it more difficult and less profitable or thieves to steal the wiring, a valuable commodity that can fetch hundreds of dollars at the area's scrap yards, according to parks and police officials.
Parks officials said they would make it harder for thieves to reach hand boxes, and would reduce the gauge, or thickness, of the copper wire they use, so that it would still meet code requirements, but wouldn't be as valuable for resale. Those efforts were expected to cost up to $30,000 alone in Wyman Park Dell.
A new viewing and recording full identification of sellers and photographing all the scrap they're selling — but said it doesn't seem to have put a dent in the problem.
The Maryland General Assembly took note of the problem and passed more stringent restrictions on scrap metal sales in May 2011. The state legislature created the Regional Automated Property Information Database, called "RAPID," to collect data about sales and sellers.
The law requires scrap buyers to note a description, including the weight and grade, of the scrap; take a picture of the scrap; record the date and time of the transaction and the money paid to the seller; and record the name, date of birth, address, driver's license number and license plate number of the vehicle used to transport the metal, and a physical description of the sellers as seen on their ID. It also requires that scrap seller send the information to local and state police.
The Regional Automated Property Information Database Fact Sheet for 2011 mentions major scrap metal thefts in six counties in Maryland as well as Baltimore City and includes a case where about $2.5 million in total of scrap metal was stolen. Police jurisdictions in as far away as Australia aided in the recovery of the metal.
RAPID's 2011 Fact Sheet touts 642 arrests, 882 cases closed and $5.2 million recovered in stolen property. It does not show figures for copper crime prior to 2011.
According to Maryland law enforcement, copper theft is not a specifically classified kind of crime. It falls under property crime, which makes it difficult to compile statistics about copper theft.
Some scrap buyers say it has helped, but not enough.
"I don't think it has been a huge deterrent," said Brian Sclar, the president of the metal recycling business Frederick Reliable. "But I do think it has been very effective in solving a number of copper theft crimes."
In February, six men were arrested for the theft of about $31,500 worth of copper wire belonging to Verizon in Aspen Hill.
"In general, accountability is a deterrent. If people know they can be traced, they're less likely to try to steal something," said Bill Toohey, communications director for the Maryland Governor's Office of Crime Control and Prevention.
Larry Perl of the Baltimore Messenger contributed to this story.