Prosecutors say the father of 3-year-old Brendan Creato, who is charged with murder in the boy's killing, committed the crime because the child was an impediment to his relationship with a teenage girlfriend, international media report.

Those details came during the arraignment for David "D.J." Creato Jr., 22, on Tuesday afternoon in New Jersey, USA. Creato is also charged with child endangerment and faces a possible life sentence if he's convicted on the murder charge.

"She repeatedly threatened to break up with the defendant, and he repeatedly begged her not to," prosecutor Christine Shah said.

Brendan vanished from his father's home in the pre-dawn hours of 13 October on the 100 block of Cooper Street in Haddon Township.

He was later found partially submerged in the water in a wooded section of nearby Cooper River Park.

It's a location that D.J. Creato allegedly told investigators was "spiritual" for him, and one he had been to some 30 times with his girlfriend, even taking a photo there.

Shah said on Tuesday investigators do not believe Brendan went to that area on his own. First, she said, Brendan's socks were clean despite the muddy surroundings.

Second, she said, family members say Brendan was afraid of the dark, so it was unlikely he would have gone into the wooded area in the pre-dawn hours.

Third, Shah said, there were no signs of forced entry at the home and Brendan slept on a love seat just nine feet from his father's bedroom door.

The prosecutor then launched into what it says is the timeline leading up to Brendan's murder.

D.J. Creato began dating a 17-year-old girl in June of 2015, and the girl had a 'dislike' of children, prosecutors say.