The prosecutor said the fire at Paul Caneiro's house was set to destroy evidence he had brought there from the crime scene, but also had another goal.
The 51-year-old New Jersey resident allegedly used gasoline to set fire to his Ocean Township home before dawn on November 20 while his wife and two daughters were inside, according to an arrest warrant.
A financial dispute motivated a New Jersey man to kill his brother, sister-in-law and young niece and nephew and set their mansion ablaze before going to his home in a nearby community and torching the residence in an elaborate "ruse" to cover up his crimes, a prosecutor Thursday.
The motive in the killings was financial, the prosecutor said, and stemmed from the brothers' joint business ventures out of Asbury Park, New Jersey.
Paul's attorney Robert Honecker previously told CNN that his client was innocent of the arson charge he originally faced, as well as any other "potential charges".
Caneiro's wife and two daughters were home when he is accused of using gasoline to ignite their Ocean Township home, which is about 10 miles from his brother's home in Colts Neck. Keith Caneiro and his family were found dead, and officials say all were slain before the fire.
"This one is the most brutal case I've seen in my experience here", said Monmouth County prosecutor Christopher Gramiccioni.
After Iron Fist and Luke Cage, Daredevil axed by Netflix
We'd say that both of 'em seem safe, but we also would've said that about Daredevil if you'd asked us half an hour ago. In contrast to a strong first season, AKA Jessica Jones Season 2 was largely panned by critics and fans alike.
AWS launches RoboMaker dev service for building intelligent robotics apps
Each of the companies operate ground facilities already but will work with AWS Ground Station to augment operations. Banco Santander's digital-only subsidiary Openbank has moved to the cloud, going all-in on Amazon Web Services .
Deutsche Bank’s Frankfurt HQ searched in Panama Papers probe
Authorities seized documents and electronic files and said they were also looking at whether others might have been involved. An internal investigation by Danske found that about €200bn (£177bn) of payments were funnelled through its Estonian branch.
He declined to disclose specifics on the motive but said the investigation is ongoing.
On Thursday morning, he was charged with four counts of murder, and one count each of possessing a firearm for an unlawful goal and possessing a knife for an unlawful objective.
The fire at the Colts Neck home burned for hours, causing it to be badly damaged.
The suspect's family was able to escape the fire without injuries.
The Monmouth County Prosecutor's Office is slated to hold a press conference regarding the charges later Thursday morning.
The fire that destroyed Keith Caneiro's home was reported at around 12:30 p.m. that same day, according to authorities.
Paul and Keith Caneiro were partners as an Asbury Park technology consulting firm called Square One and a pest control company. Workers in the area frequently saw Paul Caneiro there. He is also charged with later setting fire to his own house before rousing his sleeping wife and daughters, who were not injured in the blaze. Funeral services for the family are planned Sunday.