Raised in Brooklyn, the brothers Keith and Paul Caneiro married women from Staten Island and moved to houses in suburban New Jersey about 20 minutes apart. In 1991, Keith was the best man at Paul’s wedding. They each had children and were business partners, co-owning a technology company and a pest control business.
But now Keith M. Caneiro is dead, murdered Tuesday along with his wife and young children in their stately home in Colts Neck, N.J., which was then set on fire, law enforcement officials said.
Paul J. Caneiro, 51, was arrested Wednesday and charged with setting his own house on fire in nearby Ocean Township on the same day his brother’s family was found dead. His wife and two daughters were at home when he lit the blaze, a charging document said.
While the two events seemed to be linked, Christopher J. Gramiccioni, the Monmouth County prosecutor, did not name a suspect Wednesday in the murder of Keith Caneiro, 50, his wife, Jennifer Karidis Caneiro, 45, and their two children, Jesse, 11 and Sophia, 8.
He added, however, that residents of the area did not need to be concerned that a random killer was loose among them.
“We believe that in some form or fashion, that this family was targeted,” Mr. Gramiccioni said. He said the F.B.I. and the Bureau of Alcohol, Tobacco, Firearms and Explosives were also involved in the investigation.
He said one of the reasons that no charges had been filed in the murders was because investigators were not yet able to fully access the smoldering ruins of Keith Caneiro’s 5,700-square-foot home.
Mr. Gramiccioni added that the quadruple homicide scene was “one of most heinous cases” that investigators had ever seen.
The brothers appeared to have close ties, co-owning two businesses: Square One, the technology consulting firm, and EcoStar Pest Management, the pest control firm, both in the same building on Cookman Avenue in Asbury Park.
About 5 a.m. on Tuesday, the police received a report of a fire burning at 27 Tilton Drive in Ocean Township, Paul Caneiro’s home. According to a charging document, Mr. Caneiro is accused of using gasoline to set the fire. His wife, Susan Caneiro, and two grown daughters were home at the time, the document said.
The Colts Neck fire started in the four-bedroom home on 15 Willow Brook Road just after 12:30 p.m. A cloud of gray smoke hung over the house hours later, as firefighters continued to battle it Tuesday evening.
Mr. Gramiccioni said the bodies of Jennifer Caneiro and the two children were found inside the house. Keith Caneiro’s body was found outside the house with gunshot wounds, he said.
The children’s bodies were so badly burned that they could not immediately be identified, Mr. Gramiccioni said.
Paul Caneiro was charged with arson in the Ocean Township fire and is due in court on Nov. 28.
News of the gruesome murders rattled the affluent enclave of Colts Neck just days before Thanksgiving. Bruce Springsteen has a home there, as does David Bryan, who plays keyboard in the band Bon Jovi.
David Natelson, the business manager of the pest control firm owned by the brothers, said he was deeply shaken by the events. A candlelight vigil for the Caneiro family was planned for Wednesday evening.
“I am shocked,” Mr. Natelson said in a phone interview. “And saddened.”
The two brothers grew up in Brooklyn, with Keith attending John Dewey High School, and Paul attending Abraham Lincoln High School, according to Paul’s 1991 wedding announcement in the Staten Island Advance.
Keith, who graduated in 1985, showed an early aptitude for computers. While in high school, he got a job as a janitor at a computer store, just to be near the equipment. He later became a salesman and eventually started a computer consulting firm with his brother, according to a 2001 article in the Asbury Park Press about the business. At the time, he went by the name Keith Martin, using his middle name as his last.
The company was called Jay-Martin Consulting, which derived from the middle names of both brothers. Paul was the first employee.
Both men attended Brooklyn College, and Keith went on to study for an executive master’s degree in technology management at Columbia University, according to his Facebook page. He recently posted a picture of himself smiling with his wife in a pale blue Columbia cap and gown.
His wife’s Facebook page showed multiple pictures of their oldest son, Jesse, playing at a local gymnastics studio when he was a toddler.