A child whose body was found in a New Jersey home during a tense, 37-hour standoff died from stab wounds, authorities said Tuesday. The announcement came a day after police said his mother also died from stab wounds as well as blunt force trauma.

The mother's boyfriend, Gerald Tyrone Murphy, 38, a registered sex offender, was shot and killed during a raid early Sunday morning.

On Friday, at 2:47 p.m., police were called to a home on the 200 block of Grand Street in Trenton, N.J. Family members of Carmelita Stevens, 44, told investigators they had not heard from her in a while and that her 16- and 18-year-old daughters had not been to school in 12 days.

When officers arrived at the home, police say they forced their way inside after not receiving any response. As they walked inside, investigators say they smelled an odor consistent of that of a decomposing body. They also say they noticed maggots throughout the residence. They then say they heard a voice coming from a bedroom upstairs.

Investigators say the voice came from Murphy, a man who police say had an arrest warrant for failing to register as a sex offender. (Picture: Gerald Murphy)

As officers walked into the home, police say Murphy informed them there was a dead body in the room with him and another dead body in another room. Police say those bodies were that of Stevens and her son, 12-year-old Quavon Foster. According to investigators, they were both killed on April 25.

An autopsy revealed that Foster suffered from multiple stab wounds to the chest. His mother also died of multiple stab wounds to the chest as well as blunt force trauma to the head.

Police then say they learned that Murphy was barricaded inside the room with Stevens' three other children, ages 18, 16 and 4. Murphy also claimed he was armed with a handgun as well as explosives, according to investigators.

Investigators say Murphy held the children against their wills.

Police say they searched the rest of the home and found Stevens' 19-year-old son in the basement, unharmed. He told them that he hadn't seen his mother or siblings since April 24, a day before her death.

The bomb squad, FBI negotiators and State Troopers were all called to the scene. Family members of Stevens also arrived. Stevens' sister, Tonya Kelly, said she drove to Trenton all the way from Maryland when she heard news of her sister's death.

"They had a little misunderstanding and the guy killed her and my nephew," said Kelly.

After a standoff that lasted over 37 hours, officers finally entered the bedroom around 3:45 a.m. on Sunday. Once they were inside, they say they spotted Murphy threatening one of the children. An officer fired a single shot which struck Murphy in the head. He was taken to the hospital where he later died from his injuries. The three children were then taken to the hospital for evaluation and treatment.

Investigators are looking into whether Stevens' 16- and 18-year-old daughters were sexually abused by Murphy while they were held captive. The state's attorney general's office will handle the investigation.

Police say Murphy was Stevens' live-in boyfriend. He was not the father of any of her children however.

Stevens' surviving children remain in the hospital. Police say they won't be interviewed until they are mentally and physically well enough.

Neighbors remember Stevens as the woman who made a habit of donating her children's old clothes to others in need.

"I just thought, how could that happen to someone so nice," said Katherine Depaz.

Those who knew Murphy said they were shocked by everything that transpired.

"He's never acted like this," said Haydee Santana, a friend of Murphy's. "He has always defended the community. If he sees a lady walking in the streets, he'll walk her home."

Pennsylvania State Police have different memories of Murphy however. They say he was a violent sexual predator who was convicted of sexually assaulting a minor in 2001 and sentenced to jail. He was then placed on Megan's List.

Due to his status as a sexual predator, he had to let state police know if he changed his job or bought a new car. Police say Murphy went off their radar in 2011 and remained there until last weekend's standoff.

Pennsylvania State Police Corporal Gerard McShea says Murphy was supposed to report to state police quarterly.

"He only registered once back in January of 2011," said McShea. "He never came in after that."

State Police say this prompted an investigation and a warrant for Murphy's arrest. He was also placed on a nationwide data system alerting police to be on the look out for him. According to court records, Murphy also had convictions for aggravated assault, fire arms violation and robbery. State Police say that once Murphy slipped away and crossed state lines it became difficult to find him.