COLTS NECK - How much money could compel a man to murder his brother, sister-in-law, niece and nephew?

Paul Caneiro shot his younger brother Keith to death, then went into Keith's home, shot and stabbed Keith's wife, Jennifer, and stabbed their children, Jesse and Sophia, before setting a fire in the basement and leaving his dead relatives to burn, according to Monmouth County Prosecutor Christopher Gramiccioni.

The first fire wasn't the end of it.

Paul Caneiro then went home to Ocean Township and set fire to his own house, with his wife and daughters inside, as a "ruse" designed to make investigators believe some other person was hunting down the whole Caneiro family, according to the prosecutor.

And it was all over money, according to the prosecutor's office. The brothers were business associates in technology and pest control companies.

Caneiro, 51, has been in custody since Nov. 21, on suspicion of setting fire to his own home the day before. New complaints signed today charge him with the murders of his brother, Keith 50, Keith's wife, Jennifer, 45, the couple's 11-year-old son, Jesse, and their 8-year-old daughter, Sophia.

The complaints refer to the children only by their initials.

The family tragedy first came to light in two episodes on Nov. 20 — first when firefighters responded to Paul Caneiro's Tilton Drive home in Ocean Township early in the morning, and then shortly after noon when other first responders rushed to Keith and Jennifer Caneiro's Willow Brook Road home in Colts Neck.

In Ocean — where Gramiccioni said the origins of the fire were at two exterior points of the home — the entire family made it out safely.

Not so in Colts Neck.

A neighbor's groundskeeper smelled smoke and told his boss. The neighbor ran into Keith and Jennifer's burning home to find a body face-down on the floor.

Keith Caneiro was found dead outside the home, shot several times.

Firefighters found Jennifer, Jesse and Sophia Caneiro inside the $1.5 million home, also dead and severely burned.

At a news conference Thursday morning, Gramiccioni said investigators believed the fire had smoldered in the basement throughout the morning, "until when there was entry made into the home, a great deal of oxygen coming into that home effectively fed that fire."

COLTS NECK FIRE: How did the Caneiro home burn unnoticed for hours?

The fire Paul Caneiro allegedly set at his own home, extinguished hours before the Colts Neck fire was discovered, "served two purposes," Gramiccioni said Thursday. "One was to destroy evidence that he retained," he said.

The complaints say that among evidence seized in the case are one or more cellphones, computers or similar electronic devices.

The other purpose of the fire Paul Caneiro allegedly set at his own home was to create a "ruse" that someone else had targeted the Caneiro family at large, Gramiccioni said.

The federal Bureau of Alcohol, Tobacco, Firearms and Explosives determined both fires to be arson, Gramiccioni said.

The killings were "financial in nature, stemming from his and the victim's joint ventures that ... they owned and operated out of Asbury Park," Gramiccioni said of Paul Caneiro Thursday. "As a result we have also ... launched a financial investigation into the business and financial dealings of the defendant."

In happier times, the brothers had been business partners. Keith Caneiro's first hire when he founded his technology company in Brooklyn was Paul Caneiro. Their company, Square One, shared office space in Asbury Park with other affiliated companies — EcoStar Pest Management and Jay-Martin Consulting, a technology company that used the brothers' middle names.

In addition to four counts of murder, the complaints charge Paul Caneiro with setting Keith and Jennifer Caneiro's mansion on Willow Brook Road in Colts Neck on fire, possessing a firearm with the purpose to use it unlawfully against Keith and/or Jennifer Caneiro, and possession of a knife with the purpose to use it unlawfully against Jennifer Caneiro and her children. ​​​​​

Keith Caneiro's cause of death was the gunshot wounds he sustained, but Jennifer, Jesse and Sophia Caneiro's causes of death are still pending test results, Gramiccioni said.

Reached early Thursday morning, Mitchell J. Ansell, one of Paul Caneiro's attorneys, said he and his associate, Robert A. Honecker Jr., would have a statement on the new charges following the news conference at the prosecutor's office.

Ansell and Honecker, of the Ocean Township law firm Ansell, Grimm and Aaron, have repeatedly asserted their client's innocence.

"My client adamantly maintains his innocence and adamantly maintains that he would never hurt his family,'' Ansell told the Asbury Park Press Wednesday night.

Paul Caneiro was originally scheduled for a court appearance Wednesday, but his attorneys requested a postponement until Friday to review new evidence. It was unclear whether the defense attorneys would request another postponement in light of the new charges.

Gramiccioni said Thursday the quadruple homicide was the most "brutal" crime he has seen in his time at the prosecutor's office, and offered his condolences to the victims' family members and friends.

"It's not lost upon us how troubling and confusing this incident has been to you and how unusual these circumstances are as alleged," he said. "We won't stop until we bring justice in the name of Keith Caneiro and his entire loving family."

This is a developing story. Stay with app.com for updates.

MORE:

Paul Caneiro's lawyer says his family will vouch for him

What we know about the Caneiro murders

Alex N. Gecan: @GeeksterTweets; 732-643-4043; agecan@gannettnj.com

Kathleen Hopkins: @KHopkinsapp; 732-643-4202; Khopkins@app.com

Contributing: Andrew Goudsward