When they stopped to fill their gas tanks recently, several Takoma Park residents realized something wasn’t quite right. As they pumped, a puddle of gasoline began to pool at their feet.

This was no typical car trouble, though. Police said the drivers had fallen victim to thieves who drilled into their tanks and made off with the fuel — an attractive target, considering today’s gas prices.

Police believe that the incidents, which can be dangerous because gasoline vapors are flammable and can ignite with a spark, occurred overnight and on weekends. Police are still looking for who committed the crimes.

There’s no doubt that thieves are attracted to certain easily portable, high-value items: iPhones, laptop computers, cars’ Global Positioning System devices. But police say those looking to steal also go after loot that might be less obvious — but that can still bring a quick buck.

“Thieves continue to come up with different scams and different items to steal to make money,” said Fairfax County police spokeswoman Lucy Caldwell. “That’s one thing that will probably never change.”

Around the Washington region in recent months, people have swiped catalytic converters from parked cars — valuable because they contain trace amounts of precious metals, including platinum, and can be sold for cash at scrap yards. They have snatched newly delivered packages from doorsteps.

Sunglasses and coins have disappeared from locked and unlocked cars. A man in Charles County was charged with a string of tire and rim thefts. Work vans have been looted for tools.

Prescription medication has been swiped from homes. Vienna police officers said they recently charged a few people who allegedly were casing cars specifically to steal liquor.

“You think it’s strange — ‘that’s funny, they stole my gym bag’ — but nothing is really unusual,” said Officer Rebecca Innocenti, a Montgomery County police spokeswoman.

In a recent string of Montgomery thefts, the thieves walked up driveways and lawns, sometimes in daylight, to carry out their crimes, police said. When residents questioned them, they claimed to work for a gutter-cleaning company.

The group wasn’t after jewelry or flat-screen TVs. They were there for copper.

In all, police said, the thieves struck 26 times over three winter months in Bethesda, Potomac and Rockville, swiping downspouts and gutters made of copper, a metal that brings a high resale value these days.

Takoma Park police said the seven gas tank drillings were reported between November and January.

Some of the victims had not driven their cars for several days and thought nothing of it when they found their tanks were nearly empty — until they made a trip to the gas station. Others immediately noticed a strong odor of gas.

Takoma Park police crime analyst Andrew Gucciardo describes the drillings as “necessity thefts.”

“In a tough economy, people are more likely to take things of necessity,” Gucciardo said.

In addition to the gas thefts, which can mean costly repairs for car owners, Gucciardo said, there has also been a rash of diaper and laundry detergent thefts from retailers. Washington area residents have recently reported that clothing and frozen food have been stolen, police said.

To limit the chances of falling victim, police encourage locking car doors and hiding all valuables, including items that might not seem worth stealing.

“We have people that just go around and try door handles” said Vienna police spokesman Bill Murray. “If they find anything inside, they just take it.”

Similarly, unlocked windows, patios or garage doors make homes good targets.

To keep cars safe from gas thieves, AAA Mid-Atlantic recommends parking in well-lighted areas and reporting suspicious behavior — people who seem to be lurking around parked cars, for instance. If you notice dripping gasoline or smell gas, call a garage or a tow truck.

Thieves have learned a tactic of targeting cars without attracting attention by breaking glass and without testing door after door. They have been known to comb fitness clubs for lockers they can open, take car keys and go through the nearby streets and parking areas pushing the keyless entry button. The beeps lead them straight to their bounty. Stephen Chaikin, a longtime prosecutor in Montgomery, said gym-goers should lock their keys in lockers.

Another recent trend to target copper: thieves ripping entire HVAC units from the outside of houses, loading them onto trucks and driving off. Although the units might be worth more than $2,000, the thieves are only interested in the copper components they can sell for a fraction of that, Chaikin said.

Prince George’s County police officers said they’ve seen thefts of air conditioning units, too, and that homes being renovated or vacant for other reasons are particular targets. Lt. Brad Pyle, who commands the Prince George’s County Police Department’s organized retail crime unit, said a quick call to police can help combat the problem because detectives there track scrap metal.

An item’s value to a thief is subjective, said Murray, the Vienna police spokesman. Police there have responded to reports of stolen copper wire, liquor and construction tools. “Just about anything they can find,” he said.

Some car owners leave their cars unlocked to prevent criminals from damaging their cars while breaking in. Innocenti advises otherwise, saying that gives criminals an easier shot at stealing the vehicle and possibly using it in another crime.

The list of potential valuables to a would-be thief seems endless. But police say common sense is a powerful deterrent.

Almost half the break-ins in Howard County are done without using force, according to county police spokeswoman Elizabeth Schroen. “The biggest tip is obvious,” she said. “Lock everything up, and you can prevent theft.”

Staff writers Katherine Driessen, Dan Morse and Matt Zapotosky contributed to this report.

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