The first day of testimony in the trial of a man who is accused of killing an adult and two children took place on Monday.

Paul Caneiro is accused of killing his brother Keith and Keith's family, then trying to cover it up back in November 2018.

During opening statements, assistant prosecutor Nicole Wallace said there is a recorded phone conversation between Keith and Paul that will be played in court made just hours before the murders. The defense also began to lay out a potential strategy by pointing fingers at a third brother, named Corey, who would also benefit from a life insurance policy.

“In the dark, the defendant hunted them down, he stabbed his sister-in-law Jennifer multiple times and shot her in the head. He stabbed Jesse multiple times through his arm into his chest, and he stabbed Sophie 17 times over her entire 45-pound body, including deep stab wounds in face and head,” said Wallace.

Prosecutors went over the events they say took place during the early hours of Nov. 20, 2018, as accused killer Paul Caneiro sat mostly stone-faced, staring straight ahead. Assistant Prosecutor Nicole Wallace told the 12 men and four women seated in the jury box how a brother and business partner turned into a killer, motivated by money.

“On Nov. 19, 2018, the defendant's house of cards was about to come crumbling down. The evidence will show Jesse and Sophia were still alive and breathing after their uncle repeatedly stabbed them. Still alive and breathing after their uncle set fire to their home and left them. Still alive and breathing as the smoke began to rise from the basement,” said Wallace.

Paul Caneiro’s attorneys say he didn't kill anyone or set fire to his house or his brothers.

“Sometimes the police are wrong. Who should the police have focused on? Who should they investigate? They didn't mention him, but there's a third brother - Corey Caneiro. They didn't tell you the terms of the trust were such that in the event something happened to Keith and family that $3 million would get divided - $1.5 million to Paul Caneiro and the other $1.5 million to Corey Caneiro,” said Caneiro’s attorney Monika Mastellone.

The first witness to testify was a former employee of the Doris Duke Foundation. The foundation was the main source of income and client for Keith and Paul's Square One Tech Consulting firm. She testified contract negotiations were underway to renew when Keith was killed.

Ronald Artiges, an insurance agent who knew the Caneiros, testified on the morning of Nov. 20, Paul filed a claim around 9 a.m. following a fire at his Tinton Falls home, a fire prosecutors say he set after committing the murders and torching the Colts Neck mansion.

Caneiro is facing life in prison if found guilty.