The suspect, identified as Gerald Tyrone Murphy, 38, was shot once when police entered his home to rescue the children early Sunday; he died later at a hospital, The (Trenton, N.J.) Times reported.
"Following our entry, a single shot was fired by our entry team to stop a hostile action against one of the children," said New Jersey State Police superintendent Col. Rick Fuentes.
The standoff began Friday after police conducting a wellness check at the home discovered the decomposing bodies of Murphy's girlfriend, identified as Carmelita Stevens, and one of her children, officials said during a press conference Sunday. Police believe Stevens and child were killed about two weeks ago.
Stevens, 44, and her five children had been living with the Murphy for about two months, The Times reported. Her children include a 19-year-old autistic son, who was rescued from the house on Friday before the standoff, and two daughters, ages 18 and 16 and a 4-year-old boy, who were all rescued during the standoff. Another one of her sons who was in his early teens was allegedly killed by Murphy.
The surviving children were brought to local hospitals for treatment.