LOS ANGELES: When a gang member was released from jail soon after his arrest for selling methamphetamine, friends and associates assumed he had cut a deal with authorities and become a police informant.

They sent a warning on Twitter that went like this: We have a

snitch in our midst.

Unbeknownst to them, that tweet and the traffic it generated were being closely followed by investigators, who had been tracking the San Francisco Bay Area gang for months. Officials sat back and watched as others joined the conversation and left behind incriminating information.

Law enforcement officials say gangs are making greater use

of Twitter and Facebook, where they sometimes post information that helps agents identify gang

associates and learn more about their organisations.

“You find out about people

you never would have known about before,” said Dean Johnston with the California Bureau of Narcotics Enforcement, which helps police investigate gangs. “You build this little tree of people.” In the case involving the suspected informant, tweets alerted investigators to three other gang members who were ultimately arrested on drug charges.

Tech-savvy gangsters have long been at home in chatrooms and

on Web sites like MySpace, but

they appear to be gravitating

toward Twitter and Facebook, where they can make threats, boast about crimes, share intelligence on rivals and network with people across the country.

“We are seeing a lot more

of it,” Johnston said. “They will

even go out and brag about doing shootings.” In another California case involving a different gang, much of the information gathered by investigators came from members’ Facebook accounts. Authorities expect to make arrests in the coming months.

“Once you get into a Facebook group, it’s relatively easy,” Johnston said. “You have a rolling commentary.” And gang members sometimes turn the tables, asking contacts across their extended networks for help identifying undercover police officers.

It’s hard to know exactly how many gang members are turning to Twitter and Facebook. Many police agencies are reluctant to discuss the phenomenon for fear of revealing their investigative techniques.

Capt Walt Myer, director of the Riverside County regional gang task force, said gang activity often “mirrors general society. When any kind of new technology comes along, they are going to use it.” Tapping into tweets and status updates

can be easy. Agents pose as

pretty girls and send flirtatious friend requests. Confidential informants sometimes let police peer into their accounts.

Authorities can also seek help from the Web sites. Representatives from Twitter and Facebook say they regularly cooperate with police and supply information on account holders when presented with a search warrant. Neither company would discuss specifics.

Gang use of Twitter and Facebook still lags behind use of

the much-older MySpace,

which remains gang members’ online venue of choice.

The Crips, Bloods, Florencia 13, MS-13 and other gangs have long used MySpace to display potentially incriminating photos and videos of people holding guns and making hand gestures. They also post messages about rivals.