En Español.

Ads for the iPhone are filled with promises that the “thinnest smartphone around” allows you to work, play and listen longer. Now the device that inspires such superlatives can add another: most wanted by thieves.

“Smartphones are really valuable to criminals, especially iPhones,” said Lt. Mark Coda from the San Francisco Police Department. “I rarely hear of Blackberries getting stolen.”

The trend-setting iPhone — some 18.6 million were sold in the first quarter of this year — has also created a thriving black market, and iPhone theft is a growing problem across the country.

You say you’ve password-protected your iPhone and it has a tracking device? No matter. Criminals find those as easy to neuter as downloading a farting app.

“Lots of these guys are sophisticated,” said Coda. He’d heard of only two cases in which phones were recovered by tracking apps like Find my iPhone.

Richard Doherty, co-founder and director of a technology assessment and market research firm, the Envisioneering Group, agreed. But, he added, the thief doesn’t even have to be that smart.

“Anybody can use a stolen phone,” he said. There are many apps that allow any iPhone to be unlocked, plus there are plenty of software programs online that allow anyone who has access to the Internet to unlock a phone. Typing “How to crack an iPhone” into a search engine leads millions to the many how–to guides available.

An Apple spokesperson said the company’s Find my iPhone app, which can also delete the owner’s personal data, gives it an advantage over other smartphones. He added that all smartphones are vulnerable, and that theft shouldn’t be seen as an iPhone-only problem.

But in San Francisco, at least, iPhones appear to be the most popular problem. Erica Terry Derryck, a spokeswoman for the District Attorney’s office, agreed that there has been an uptick in all smartphone thefts, but that iPhones are taken more often. They’re popular, and owners often use the distinctive white earplugs that make them easy to identify for muggers “on the fly,” Derryck said.

In San Francisco, iPhone users become victims most frequently as they exit public transportation, pull out their cell phones and begin texting or checking email. BART stations and Muni stops offer a pool of easy targets, where iPhone rustlers can take their choice, nab their thin quarry and disappear into the crowd.

Victims can go online and use their phone’s tracking device to see if their iPhone is still in the vicinity. But even if it is, retrieving it is most often an illusion.

“Good luck with that,” said Lt. Coda. In densely populated areas, police can do little because they can’t stop and pat down everyone in the vicinity.

And it’s not always wise for civilians to try to retrieve their phone on their own. The Philadelphia Daily News reported recently that after a young man’s phone was stolen at a party, the victim and his buddies tracked it down but ended up assaulting the wrong man. The men in the iPhone posse now face multiple charges.

“The tracking app is most useful with missing phones,” said Doherty, who was able to retrieve his phone when he lost it. “You can also send a text and hope someone returns it.”

The Police Department suspects that many of the phones stolen in San Francisco end up at a doughnut shop in the city, but so far they have failed to come up with enough evidence for the District Attorney.

The District Attorney’s office has no ongoing investigation of an iPhone theft ring, according to Derryck.

Police have tried using decoys on the street, but these have proven ineffective. An undercover female officer was sent into the crowd at 16th and Mission streets, only to discover that her behavior — talking freely on her iPhone — was similar to that of everyone around her.

Currently, police are trying other tactics to entice ringleaders to surface.

The BART stations at 16th and Mission, 24th and Mission and Civic Center are prime areas, but the daily crime reports also show that anyone walking anywhere with their cell phone out is a sitting duck.

Victims often tell police they were playing Angry Birds or absorbed in a conversation.

Police Department officials say they’re doing what they can to raise awareness, and to encourage iPhone users to avoid taking their phones out at isolated stops and to stand near others at bus stops.

“People should not be so engrossed on their iPhones and laptops,” Coda said.

Apple advises its customers to file a police report if their phone is stolen.

When confronted, police representatives say, be cooperative. Not even an iPhone is worth fighting for.