Your smart phone might get you punched in the face.

Cell phone robberies take place with alarming frequency all over the city, and although the police are working on the problem, there isn't much they can do about this quick, random, lucrative crime that's replaced purse and wallet snatching.

Official police statistics show that there were more than 40 cell phone muggings in November. The number may not seem high, but it is unsettling with just a portion of the crimes reported, and virtually all of them involve a gun, knife or physical assault.

"You're focused on your phone, talking, and you get sucker punched," said Tenderloin Station Capt. Joe Garrity.

Police reports read like an urban nightmare: punched repeatedly in the face, gun to head, grabbed by hoodie, thrown down ... hit with metal pipe, victim in wheelchair.

"They prey on the weak - women, handicapped, impaired and young kids," said Sgt. Mark Obrochta, who heads the undercover division at the Tenderloin Station.

I rode along on a sting operation Wednesday, which was focused on Market Street, between Fifth and Seventh streets. Garrity calls the corridor ground zero for stolen property, where you can get an iPhone 4S for $300-$400. Often, Obrochta says, the demand is global, and buyers ship the product overseas.

In one sense, our sting operation was incredibly successful. The undercover officer trying to sell an iPhone that he told people was stolen had a buyer in less than five minutes. No wonder the corner of Seventh and Market is called the Walmart of stolen phones. Obrochta says when they get a report of a cell phone mugging, they often go straight there to look for someone matching the suspect's description.

But when the team swooped down on the buyer, he had disappeared into a store with several friends. When he emerged, he didn't have the phone. With a positive identification from three undercover officers and the circumstantial evidence of some $1,400 in bills in the suspect's pocket, Obrochta was confident in making an arrest.

But the police know this won't stop the pervasive crime. Word gets out quickly that the cops are on the prowl. That shuts down the market for a few days, especially when the guy who is arrested turns out to be a regular offender.

Better odds

The truth is, the smart phone is the low-hanging fruit for roaming thugs. With debit cards in universal use, the average person isn't carrying much cash. The high-tech cell phone is probably the most valuable item you carry on the street.

"It's the modern day purse snatch - with better odds," said Obrochta. "With a purse, you never knew what you were getting."

Victims make it easy by walking down the street, holding out the phone while texting or searching for directions. "First, I am showing you that I have a nice fancy phone," said Brian Cooley, editor at large for Cnet. "And second, I am demonstrating that I do not have good situational awareness."

Cooley says he is amazed that people don't set a password on the phone for security or get insurance for a replacement. He adds that there are phone-tracker programs that will let you know where your phone is, allow you to send a message and even do a "remote wipe."

But unsophisticated muggers are probably just looking to wipe the data anyhow. They ditch the SIM card - canceling the tracker - "jailbreak" the phone with computer software to make it available for any phone network and sell it.

Recognition system

The techie dream is that some kind of recognition system would make it pointless to steal a phone. There has been talk of voice recognition, facial imagery or even detecting the owner's heartbeat. Apple has long been rumored to be working on facial recognition.

But Cooley said when an Android device debuted face recognition, some bright fellow held up a photo of the owner and was promptly approved.

"It would have to be something 3-D, so it is not fooled by a flat image," Cooley said. "Everyone is looking for the next layer of magic."

Magic, unfortunately, takes time. For now, the best move is to keep your smart phone in your smart pocket.