Thieves these days.

If they're going to steal the copper tubing from someone's house -- an increasingly common pastime for criminals -- the least they can do is turn off the gas when they leave.

Thieves broke into a house on Christopher Street in Stanton Heights sometime between Nov. 12 and Monday through the back door and made off with copper pipes from the house.

"The actors also left the gas leaking," a Pittsburgh police report says. A shutoff valve was used to stop the leak.

That incident was just one of at least eight copper capers in the city reported on Monday throughout the city.

Copper thefts are a continuing problem in Pittsburgh and across the country because the price per pound is so high, largely driven by the construction boom in China.

Thieves, often junkies, steal copper from homes or construction sites and sell it at area scrap yards so they can buy drugs.

Police also suspect that some thefts are the work of organized gangs or professional thieves taking advantage of a lucrative market.

Either way, police responded to at least seven other copper thefts in Bloomfield, Esplen, the North Side and Allentown.

One happened sometime Sunday or Monday at a house on Cypress Street in Bloomfield. The owner, who is renovating the property, told police that someone entered the house while he was gone and removed several copper pipes from walls in the basement.

Another theft, reported on Monday, happened sometime in the last week at a home up for sale on Breker Street in Marshall-Shadeland.

A friend of the owner, who lives in Texas, told police she was watching the house until it's sold. On Monday she found that someone had pried open the basement door and stolen copper piping from the ceiling and the hot water tank.

In Perry North, thieves broke into a vacant property for rent on Woods Run Avenue. While the owner's father and brother were showing it to a prospective tenant, they noticed pipes missing from the laundry and pry marks on the basement door.

The "midnight plumbers," as police call them, were also busy in Esplen. A homeowner on Florien Street told police on Monday that someone kicked in his rear door while he was away and removed copper tubing from the water heater and an adjacent bathroom sink and tub.

Another theft was reported in Esplen, on Tabor Street, where someone stole all the copper water pipes sometime between June 6 and Monday.

Two others were reported on Monday as well, both on Manton Way in Allentown.

The owner of both homes, Michael Roscoe, told police he was working on the houses on Thursday, and when he came back on Monday someone had broken in and stolen all the piping from the kitchens and bathrooms.

Mr. Roscoe said yesterday the thieves even took both water meters in the houses, but left behind other valuable items.

"There was new stuff, still in packages, that they didn't touch," he said. "Their primary goal was that copper."

He said police, who have been plagued with similar thefts, seemed to be particularly determined to catch a suspect. He said when he's had problems with tenants in the past, police were not always so helpful. But with the thefts, they dusted for prints and did a thorough investigation.

"I was impressed. This time they responded quickly," he said. "I hope they catch them."