Two men reportedly shot Friedland to death in the Short Hills Mall parking lot, where he and his wife Jamie Schare Friedland had just returned after shopping. The men reportedly ordered Jamie Friedland out of the car and stole the car, which they later abandoned in Newark.
The Friedlands own a condo on Park Avenue in Hoboken.
A funeral was held for Friedland, 30, an attorney, on Wednesday.
The prosecutors held a press conference on Saturday morning to discuss the arrests.
From late Friday through the wee hours of Saturday morning, the police arrested four men, two of whom were allegedly involved in transporting the criminals to and from the scene of the murder.
All four were charged with murder, conspiracy, and several other counts.
Those charged were three Newark men -- ages 31, 32, and 33 -- and a 31-year-old man from Irvington. Three of them were arrested at homes in New Jersey, while one was collared by the FBI at a hotel in Easton, Pa.
The suspects were captured due to "good old fashioned police work" and tips from the public, said Acting Essex County Prosecutor Carolyn Murray.
She said that the crime occurred because the suspects were looking for a pricy Range Rover to steal.
Jamie Schare Friedland issued a statement saying, "We are very grateful to the Essex County Police and all of the local authorities for pursuing this so vigorously."
The Associated Press reported, "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."