"I said: 'Oh my god!' I put my hands up, and I backed away," Amponsah said recently, describing how he watched the SUV speeding away, a vehicle for which he'd saved for four years.
Amponsah was far from alone. Carjacking, a scourge in Newark and other northern New Jersey cities in the 1990s, had reappeared swiftly, and with a vengeance, in 2010.
A rash of carjackings in December contributed to a total of Newark last year, compared with 169 the previous year, an increase of 70 percent.
Fortunately, on the same day Amponsah's car was stolen, law enforcement officials were meeting to discuss how to combat the sudden crime wave, which threatened to undermine Newark's efforts to counter negative perceptions and lure businesses to the city.
The challenge: Stop the carjackers in their tracks and calm residents' fears, at a time when the city had just laid off more than 150 police officers in a budget-cutting move.
The response was to bring to bear all of law enforcement's tools, from predictive computer analysis on the front end and an aggressive, targeted police presence to prosecutorial muscle on the back end.
The results were striking: about 30 arrests and more expected to be announced Monday by the U.S. Attorney's Office. Officials agree the interagency cooperation may be a model in future investigations, particularly in times of shrinking resources.
"I've never seen this type of collaboration in my 30 years of police work," said Newark Police Director Garry McCarthy.
The stakes were highest in Newark, where recent gains in violent crime reduction had begun to bear fruit for Mayor Cory Booker's efforts to attract business investment in New Jersey's largest city.
The carjackings made national headlines and even caused the board of directors of a company that was considering moving to Newark to start rethinking its plans, Booker said. The mayor agonized over the situation, even canceling a Christmas vacation to California to visit family, not wanting to leave a city gripped by fear.
"The problem with the carjackings was it was so indiscriminate," Booker said. "It really created an atmosphere where people felt that any of us could be a victim, and that was really troubling."
Unlike previous carjackings where thieves would strip vehicles for parts or sell them out of state, the recent wave perplexed law enforcement officials because almost all appeared to be done by thrill-seeking young men who would steal the cars for a few hours, drive them around and then abandon them.
It was quickly concluded that the extent of the problem put it beyond the scope of any one department.
The Dec. 6 crime summit brought together the State Police, the county prosecutor's and sheriff's offices, the Newark police department and its counterparts in surrounding towns and counties.
In the past, local police departments would take the lead in investigating a carjacking and request help as needed from neighboring towns.
Now, officials realized they had to get out in front of the problem.
The State Police contributed computerized predictive analysis that mapped possible future carjackings. A National Guard helicopter was offered for aerial support. Word of any carjacking was immediately dispatched to surrounding municipalities for quicker, more coordinated responses.
But the wave continued.
U.S. Attorney Paul Fishman and Michael Ward, head of the FBI in Newark, widened the effort to include the local branches of the Drug Enforcement Administration, Bureau of Alcohol, Tobacco and Firearms, Immigration and Customs Enforcement and the acting U.S.
Marshal. Those agencies, which don't normally focus on crimes like carjacking, agreed to lean on informants or investigation subjects who might have relevant information.
"The goal of all of this was threefold: To make sure that there was a unified law enforcement response to a serious violent crime issue in Newark, and that the people engaged in this conduct understood that and knew that they would be treated that way," Fishman said, "and, that the community understood that we were not going to tolerate this level of violence in the city."
The FBI provided surveillance support, both electronic and with agents on the ground who accompanied local police on arrests.
Newark sent out its best police officers in teams, flooding past and anticipated carjackings sites.
Officers made dozens of arrests, many for gun possession or stolen vehicles, thus preventing possible carjackings, McCarthy said. Investigators developed sources, re-examined unsolved carjackings, and interrogated suspects until they determined that only four or five separate groups were largely responsible for the recent wave.
Fishman and then-acting Essex prosecutor Robert Laurino examined ways to bring federal charges - or charge as adults the many juveniles arrested. State and federal sentences in some carjacking cases can reach a maximum of 30 years or more, compared to four years for juveniles.
Laurino established a special prosecutions unit to handle the cases, and attorneys and investigators used new evidence from incoming arrests to develop additional cases.
The results were nearly as swift as the spike in carjackings had been. On Jan. 10, Laurino announced the arrests of three groups of suspects believed to be linked to a large number of carjackings.
"You need intelligence-led policing in order to attack crime with less resources," Laurino said. "Using the high-tech tools that we have out there, in addition to the good old gumshoes and people with their feet on the ground, it's quite a potent combination."
McCarthy and others stress that while the problem has not gone away, it has decreased dramatically.
Now, law enforcement officials who participated in the coalition are looking at ways to use the model on other crime problems, in Newark and beyond.
"This is like the new reality in police work: We're all strapped for resources, and as a result, we all have to play in the sandbox," McCarthy said. "It's at the point where we're going to do less, but we're going to do it better, and we're going to have a bigger impact on what we're trying to do. I really think that now that's what's normal, not only here in Newark, but across the country."