The suspects were identified at a news conference as 29-year-old Hanif Thompson, of Irvington, and 31-year-old Karif Ford, 32-year-old Basim Henry and 33-year-old Kevin Roberts, all of Newark.
They are accused in the Dec. 15 carjacking and killing of Dustin Friedland outside The Mall at Short Hills. The 30-year-old lawyer from Hoboken was shot in the head in the mall parking garage after being confronted by two carjackers, authorities said. The assailants drove off in his silver Range Rover, which was found the next morning in Newark, about 10 miles from Short Hills.
The four face charges of murder, felony murder, carjacking, conspiracy, possession of a weapon and possession of a weapon for unlawful purpose. They were arrested between late Friday and early Saturday. Three of them were taken into custody at their residences in New Jersey, and Henry was arrested by an FBI task force at a hotel in Easton, Pa.
The suspects are being held on $2 million bail each but have not yet been formally arraigned. It wasn't immediately clear if they had attorneys, and their home phone numbers weren't listed.
Acting Essex County Prosecutor Carolyn Murray attributes the swift arrest to "good old-fashioned police work" and leads from the public.
"The sheer senselessness of this case outraged people from Millburn to Newark," Murray said, referring to towns in Essex County, whose borders encompass crime-plagued Newark to the east as well as Millburn, Short Hills and other affluent suburbs to the west.
Murray said the crime appeared to have been motivated by the particular type of vehicle the suspects had been looking for.
The carjacking occurred just as Friedland and his wife, Jamie Schare Friedland, were ending a shopping trip. Mourners at Friedland's funeral Wednesday said he had just opened the door of the SUV for his wife when he was shot. His wife was unharmed.
Friedland had a law degree from Syracuse University and was project manager at his family's heating and air conditioning and heating company.
"We are very grateful to the Essex County Police and all of the local authorities for pursuing this so vigorously," Jamie Schare Friedland said in a statement issued Saturday afternoon.
Investigators believe the four suspects arrived at the mall in a Chevrolet Suburban. Two left together in the Suburban, and two left in the Friedlands' SUV, Murray said. Authorities did not disclose the relationship between the suspects. No weapon was recovered, Murray said.
U.S. Attorney Paul Fishman, who attended Saturday's news conference with local, state and federal authorities, said a multiagency task force set up three years ago to combat "an epidemic of carjacking" in Essex County had helped lead to arrests in the case.
There were 416 carjackings last year in Essex County, a 44 percent increase from 2010.
Nearly 300 carjackings were reported through July 31 of this year, according to the county prosecutor's office.
More than $40,000 was offered for information leading to the arrest of the killers in this case.