More than a billion people are connecting on Facebook in the digital era, and as New Orleans police discovered in their online sleuthing, that includes several members of the Fast Money Gang.

The street gang, operating in and around the 2300 block of New Orleans Street in the 7th Ward, has been blamed for a host of violent crimes in the city. Its associates have flaunted their gang affiliation on the social network, uploading menacing group photographs that help investigators trace their associations.

Detectives scour these Facebook profiles for evidence of drug dealing and other criminal activity — some feature photos of firearms and stacks of cash — studying gang members’ “likes,” contacts and hand signals, court documents show.

“Several of the accounts have Fast Money Gang or ‘E-Block’ listed as the owner’s place of work or school,” Detective David Barnes wrote in an application for a search warrant last fall, seeking and receiving judicial approval to peruse private messages and the digital histories of at least seven profiles.

The case highlights an investigative tool being wielded now more than ever by law enforcement amid the explosive growth of digital communication: social media.

Seeking to harness a torrent of data gushing from smartphones and computers, authorities are increasingly surfing Facebook, Twitter and YouTube, among other popular websites, for investigative leads and evidence they can use to solve crimes. Just as if they were patrolling a neighborhood, police monitor social media websites to contact witnesses, identify suspects and look for chatter that might signal potential violence.

“People will go on social media and brag about acts that they’ve committed,” said Capt. Doug Cain, a Louisiana State Police spokesman. “Certainly, if we have access to it and find it, we’re going to make that part of a case.”

Last year, the FBI in New Orleans used a date of birth published on an alleged pedophile’s Facebook page to verify his identity, according to court documents. But in many cases, investigators are diving below the public surface of social media, obtaining warrants to search private Facebook messages and collect network histories they hope will guide them to fugitives.

In late April, investigators with the Louisiana Department of Justice’s Fugitive Apprehension Unit obtained geo-location information and private messages connected to the Facebook profile of a New Orleans woman accused of filing a fraudulent tax return in the name of a professional athlete. Within a week, she was arrested.

“The technology that has become available to law enforcement is unbelievable, and if you’re not on the cutting edge when it comes to social media investigations, you’re going to miss out on some valuable information,” Covington Police Chief Tim Lentz said. “People are not the brightest when it comes to what they post, and absolutely cases have been made by their Facebook posts and their Twitter pages.”

Usage is growing

A survey last year by the International Association of Chiefs of Police found that 86 percent of law enforcement agencies are using social media in criminal investigations, up from 62 percent in 2010. Altogether, 96 percent of agencies surveyed in late 2013 reported using social media in some capacity, and more than half are using Facebook to create fake profiles for undercover investigations — a violation of the website’s terms of use.

“Social media has really become an integral part of what law enforcement does, both from an investigative standpoint and for community outreach and engagement,” said Nancy Kolb, a senior program manager at the International Association of Chiefs of Police.

Trooper First Class Jared Sandifer said he used Facebook on a regular basis when he worked as a computer-based investigator for the Louisiana State Police. In at least one case he cited, social media helped authorities nab a fugitive. “He actually posted online where he worked,” Sandifer said. “And we went and found him at his job. ... That’s happened several times.”

Early last year, deputies with the East Baton Rouge Parish Sheriff’s Office noticed chatter on social media that included threats of violence in and around the Mall of Louisiana. Equipped with that information, authorities increased their patrols for the night. Although they spent hours breaking up disturbances among hundreds of minors, no one was injured, said Casey Rayborn Hicks, a Sheriff’s Office spokeswoman.

Social media can be useful in crisis situations, too.

John Selleck, an FBI agent in New Orleans, said authorities encountered a situation not long ago in which a man holding hostages accessed the Internet through social media. “Had we not been monitoring that,” Selleck said, “we would have missed out on this insight into this deranged individual’s mindset with regard to hostages. So it’s not only the protracted, long-term investigation, but it’s also in critical incidents where we’re looking at this.”

Social media also have enabled law enforcement to engage in a two-way conversation with the public. Cain, the State Police spokesman, said his agency regularly receives fruitful tips from the public on its Facebook page, which has more than 75,000 “likes.”

Until recently, many investigators had been self-taught in their use of social media. But more agencies are now receiving formal instruction about navigating the digital world, said Lauri Stevens, founder of LAwS Communications, a Massachusetts organization that hosts conferences dedicated to the use of social media by law enforcement.

Nearly all large police departments have a system in place for watching social media, she said, and some employ “very high-end tools.”

“The investigators I work with tell me there isn’t a case they work anymore that doesn’t have at least some kind of connection with social media,” Stevens said.

Tracking gang members

A number of recent cases have underscored the use of social media by law enforcement. New Orleans police declined to discuss their use of Facebook to track the Fast Money Gang, citing the sensitivity of the investigation, but authorities appear to have arrested at least some of the members whose profiles were targeted last year.

One of the gang’s alleged associates, Danshaun Hampton, was booked in the fatal shooting this month of Johan Kenner, a talented football player at Landry-Walker High School who was gunned down at St. Roch Playground.

Police also are scrutinizing the Facebook profiles of a gang referred to in a search warrant as “RSG, WSG and/or D-Block”; it’s a recent investigation in which officers sought access to accounts of living and slain members alike.

In another case, court documents show, police used Facebook to identify a suspect in an aggravated burglary in which a saw-wielding man barged into a home and attacked a resident.

A similar tactic recently was employed by federal authorities who recognized an unmistakable Facebook profile photo of a fugitive they were seeking to identify. The suspect, Kory D. Kreider, allegedly tried to run over federal agents in a Burger King parking lot in Metairie after accepting a shipment of Xanax at a nearby mailing center.

“It’s fair to say the vast majority of the investigations we do have some kind of connection to social media, whether it’s Facebook accounts, video messaging, Snapchat or Kik,” said Bryan Cox, a spokesman for the U.S. Immigration and Customs Enforcement, referring to the agency’s role in child pornography and human trafficking investigations. “Next year, it will be ones we’re not even talking about yet.”

Follow Jim Mustian on Twitter, @JimMustian. Follow Ben Wallace on Twitter, @_BenWallace.