At first glance, the baby-faced defendant in the Fulton County courtroom looks like he should be somewhere else, like wandering the high school cafeteria.

But Jonathan Redding, slight and sullen with gang tattoos marking his face, has become the picture of something gone terribly amiss.

The 19-year-old, convicted in the January 2009 killing of a Grant Park bartender during a robbery, is allegedly a member of 30 Deep, a street gang in one sense but more so a configuration of like-minded teens and young men with a penchant for mayhem.

Police say their members are responsible for an endless run of crime: smash-and-grab burglaries of tony retailers such as Saks Fifth Avenue and Nordstrom; dragging off a downtown ATM with a stolen car; and shooting a witness to a murder. But, unlike their high-profile misdeeds, 30 Deep and their compadres are more difficult to track than the gangs of yesteryear because of their loose organizational ties.

Police trace the group’s origin to chance encounters of old-school gangsters returning home from prison stints to find young, eager listeners in the neighborhoods.

What emerged from those tutorials was the formation of criminally minded cliques based out of the Atlanta neighborhoods of Mechanicsville and Pittsburgh. Unlike the old gangs, who stayed close to their turf, usually around Atlanta’s housing projects, 30 Deep members are harder to predict. They venture out, traveling to metro area cities such as Dunwoody, Lawrenceville and even Dawsonville to commit their brazen crimes.

What makes them harder to identify is a lack of permanent members, no real code or hard and fast leadership, with “members” drifting in and out.

“They intermingle; they come together to commit crimes and then span out,” said Lt. Johnny Fagler, head of the Atlanta police gang crime unit. The amorphous nature of 30 Deep and its persistence has made the gang perhaps the city’s most problematic.

That made last week’s roundup of suspected gang members — Operation Zero Deep —even more difficult. Police questioned those arrested in hopes of developing leads or put together rosters of the most recent affiliations.

Not that police haven’t seen worse when it comes to gang activity. Gangs from the crack-fueled days of the late 1980s and early 1990s were brutal.

“They were much more violent in the ’90s, much more territorial. Now they’ll move to wherever there’s money to be made,” said Fagler. “You don’t have O.G.s, original gangsters, around here. You don’t have hierarchy, you don’t have leadership.”

It was about five years ago when the fledgling gang came to police attention. In 2006, police found a student at an Atlanta high school wearing a shirt saluting 30 Deep, with a list of 30 street nicknames. They checked into it.

“We found out there were more than 30, many more. Many were adults and career criminals,” Fagler said.

They discovered that 30 Deep was really an umbrella group, including factions from surrounding neighborhoods who called themselves things like DRC, “Da Robbing Crew,” or YRC, “Young Robbing Crew.”

By 2008, 30 Deep and its splinter groups were running full on, committing frequent smash and grabs under the media moniker “Blue Jean Bandits,” attention they delighted in.

Authorities beefed up gang-crime units and tried, with varying results, to gain inroads into the various crews’ mind-sets and to suppress their actions.

Last month, George “Keon” Redding, an especially violent member and the closest thing 30 Deep has to a leader, was sentenced to life in prison. Redding, who is Jonathan’s cousin, killed two men, one with an AK-47, and then hunted down and shot a witness. His actions in Southside Atlanta brought him both awe and fear.

Interviews with residents of the neighborhoods, including victims and associates of the gang, found few who would speak on the record, or even at all. A witness in the latest Redding trial was shot last month and had to have a leg amputated, forcing a postponement in the proceedings. No arrest has been made.

Authorities say it has been difficult to keep suspected gang members locked up for long.

In December 2009, five teens suspected of being 30 Deep members were arrested and charged with committing smash-and-grabs. But a year later, just one remained in jail. The other four pleaded out in Fulton Superior Court and were sentenced mostly to time served.

In January 2010, another four suspected 30 Deep members were caught with a stolen car still idling outside while they were inside a home divvying up a cache of stolen blue jeans. They were arrested for burglary, participating in a criminal street gang and other charges. They, too, pleaded out and have been released. All four have been arrested again on other charges.

“All we can do is arrest them,” Fagler said with a shrug. The revolving door in Fulton’s criminal justice system has been an issue for years. An overcrowded jail and packed court calenders force court officials to allow defendants to plea out and get relatively light sentences. Police hope continued arrests of gang members will push judges to mete out longer sentences.

Fagler, a veteran of the force, tracks 30 Deep’s origins to another group being released from prison. Six or seven years ago, a few older criminals returned to their old stomping grounds and wowed a younger generation with stories of their gang-banging glory days.

Those times weren’t so long ago, but the 1990s seemed a lifetime away to a legion of inner-city teens. The stories sounded exotic to youths eager to hang onto something. The “old-timers,” in their late 20s or early 30s, teamed up with the eager young protégés in Pittsburgh and Mechanicsville, neighborhoods just south of downtown. And a new crime wave was born.

“If you went back and did a family tree, you could go back to the Pittsburgh Gangsters,” said Fagler.

Criminally minded young men, and even those looking to gain credibility with their peers, took to the tales of their elders. They came up with “30 Deep,” so named for lyrics in hip-hop songs that talk about rolling with crews that are 30 deep.

The gang and its affiliates started getting noticed in 2007 when members repeatedly stole vehicles, smashed them into store entrances and then scurried in to snatch electronic equipment or clothes. Other members were getting involved in armed robberies on the street.

Later in the year, on July 1, 2007, a man named Victor Hill was shot to death in a fusillade of bullets fired by several men. A woman bystander, who had just put a child in a car seat, was shot in the leg. One of the shooters, the one wielding the “chopper,” or AK-47, was 19-year-old Keon Redding, who, until then, possessed an unremarkable rap sheet.

Princeton Henry, a man who witnessed the killing, was shot and wounded by Redding four weeks later. He told police there was no real target. Redding apparently was angry at those who lived in the apartments along Boulevard near North Avenue. “The word was he was going to just come down and shoot everyone he sees,” Henry said.

A month later, Redding approached a lifelong friend, Johnquavious Broome, put a gun to his head and robbed him.

Broome’s mother, Tonya Daniel, said Redding used to eat dinner with their family. She was stunned when she heard what her son’s childhood friend had done.

“Then he called my son two weeks before he was sentenced and apologized,” she recalled. “He said he should never have robbed him, that things just went bad and got out of control.”

But, if 30 Deep members are feared by some, they also are held in high regard by others. At times they peddle high-end flat-screen televisions from their car trunks. And they always seem to walk around with pocketsful of money.

To many teenagers, the lure of 30 Deep seems inviting.

Along Bass Street, four young teens start laughing when asked about the gang. “We’re 30 Deep,” said a teen, perhaps 15, flashing a roll of $20 bills.

Many in the Mechanicsville neighborhood complain more about police harassment than gang crime.

“I think 30 Deep are all locked up or gone; it’s just a name,” said Tina Goodman, a Mechanicsville resident sitting on a porch. She asked her teenage daughter about her classmates.

“They are in 30, but they are YRC,” the girl said, referring to the Young Robbing Crew.

“But that doesn’t mean they do that,” Goodman quickly added.

Dominic Stokes, who runs an Atlanta youth program, is interviewing gang members for a documentary. Gangster life appeals to teens, even if it’s just for style or to be cool, he said. But many inevitably join in on criminal actions.

Compared to when he was a teenager two decades ago, Stokes said gang members seem to be everywhere — in music, television, movies, right around the corner.

“There’s so much more exposure now,” he said. “There’s the Internet and Facebook. They even post their crimes. It gives them credibility and clout.”

And possibly a new crop for the future.