Out front, a couple of regular customers pulled up in a Mercedes-Benz E350. The passenger got out, but the driver remained behind the wheel, talking on a cellphone. Nearby, four young men lingered, their faces covered with scarves and hoods, eyeing the car as they walked past it twice, the store owner recalled.

One of the men jumped into the passenger seat and told the driver to get out, the store owner said. The driver resisted and slammed the car into reverse, hitting a parked Jeep with enough force that it tossed the assailant from the car. A shot was fired. The men fled, leaving the car behind and its driver wounded.

The episode was among the latest in what has been an epidemic of carjackings in Newark, a gnawing reality for those forced to drive within the city's borders. The crimes have also spread to neighboring suburbs.

"It is like a diseased town," said the store owner, who spoke on the condition of anonymity for fear of retribution from the assailants, who have not been caught. "There are a lot of predators."

The problem of carjackings in and around Newark was brought in sharp relief two weeks ago, when a young lawyer was shot and killed as he struggled with assailants intent on stealing his 2012 Range Rover in the parking garage of the Mall at Short Hills, a retail center in Millburn, N.J., that attracts the affluent.

Three of the young men who were eventually arrested and charged in the crime were from Newark. A fourth man was from the neighboring town of Irvington.

Carjackings are nothing new to Newark, a city that was among the nation's worst for such crimes in the 1990s. Like other cities, Newark saw the number of carjackings fall in subsequent years. But they have returned to Newark with a vengeance.

In 2007, there were 208 reported carjackings in all of New Jersey. In 2012, there were 345 in Newark alone, 56 of which took place in December, according to the Newark police.

Already this year, there had been 475 carjackings in Essex County as of Friday, the vast majority of those in Newark, according to the Essex County prosecutor's office. In contrast, New York City had seen 159 carjackings this year as of Friday, and there has been a general decline over the last five years, the Police Department said.

 One law enforcement official in New Jersey, who spoke on the condition of anonymity, likened the trend in Newark to a "ride-share program" for criminals.

The rise in carjackings comes at a time that Newark is experiencing high rates of other violent crimes. With a population of less than 300,000 people, Newark has already seen at least 100 murders this year, and the feeling of lawlessness among some residents is palpable.

Law enforcement officials and criminologists also said that Newark's proximity to major ports — one in Newark and another in nearby Elizabeth — has contributed to the increase, giving thieves the ability to move stolen cars quickly to overseas markets. Indeed, in some cases, carjackers are simply looking for a car they can use to commit another crime and then dump. Some are targets of opportunity; others are orchestrated by organized car-theft rings that send vehicles for resale in Africa, law enforcement officials said.

This year, the victims included a Newark politician, an off-duty police officer and a police sergeant. The trend is so acute that it has inspired a Twitter account, @NewarkCarjacked, which alerts followers to most new cases.

Paul Telekian, the owner of Empire Auto Body in the city's Ironbound section, said some of his clients refuse to drive to his shop. So he arranges to meet them in West Orange, and drives the cars in himself.

"The insecurity is deep now," he said.

On the same day the lawyer, Dustin J. Friedland, was killed, three men wearing ski masks and brandishing a handgun carjacked a man in South Orange, another Newark suburb, fleeing with his Land Rover, according to the South Orange police. Although some law enforcement officials speculated that the two crimes could be related, there was no evidence connecting the carjackings, the police said.

Efforts to address the problem have yet to yield significant results. Responding to the spike in carjackings, New Jersey in 2010 created four regional task forces composed of municipal, county, state and federal law enforcement personnel, to assist with investigations. Those task forces have mainly dealt with investigating carjackings, rather than preventing them, officials said.

In August, Essex County unveiled billboards with the photos of convicted carjackers set against images of jail cells.