The boyfriend of a woman who killed herself and their three kids was pounding on her apartment door in a rage for 30 minutes before she drove the family van into the Hudson River.

Neighbor Latoya James told the Daily News that the angry confrontation started around 6:30 p.m. Tuesday, when Jean Pierre - in apparent violation of an order of protection - arrived at the Newburgh residence.

"The dad was banging on the door real loud," James said Friday. "He called to her, 'Open the f------ door!' He was there about a half an hour - he was on the phone as well."

The dispute ended with a tender moment between Jean Pierre and 10-year-old Lashaun Armstrong, the lone survivor after his mother drowned herself and his three siblings in the brackish water.

"He came down and opened the door ... He said, 'Daddy, I love you,'" recalled James, 30. "He said, 'I love you too, man,' and kissed him on the forehead."

About 15 minutes later, James watched Lashanda Armstrong load her four children into the van and drive off - a six-block ride that ended with all but Lashaun dead inside the vehicle.

The relationship between Pierre, 26, girlfriend Armstrong and their three children was often combative, with many fights sparked by his infidelities, neighbors said.

An April 12 order of protection forced Pierre to avoid contact with his 2-year-old son, Lance.

Pierre was arrested after the tot was found at 1:15 a.m. on Feb. 7, wandering barefoot and half-naked through the snow, police said.

A neighbor called cops to the scene, and authorities later said he claimed that he had walked to a nearby gas station in the early morning hours after Super Bowl Sunday.

"(Lance) kept saying, 'Where's my daddy?' " neighbor Mike Lawrence, 26, recalled of the tot. "He was mostly naked, with his pants down around his ankles in the snow.

"The father came back and asked who had his son," Lawrence continued. "He was with this woman."

Lashanda Armstrong and her four children.

Pierre was arrested three days later for endangering the welfare of a child, while Shannel Baez, 20, was busted after she falsely claimed to be the child's mother, police said.

The order of protection also barred Baez from contact with the boy.

Lawrence said that Pierre asked him to lie to Lashanda about the other woman. "If I had known now what I know now, I would have told her," Lawrence said. "Now that's on me."

Pierre was also barred from any contact with the kids at their day care center.

A few weeks ago, Armstrong ordered the staff to remove Pierre from the list of people who could call about the kids or pick them up.

"John Pierre would sometimes call to ask, 'Are my children OK?'" said Desiree Watson, owner of the Young and Unique Christian Development day care. "But we could not tell him."

Pierre was released Wednesday night after questioning by police, and was unlikely to face charges.

Leshaun returned Thursday to the Hudson River, staring at the murky waters where his suicidal mom capped a death ride that killed her and his three siblings.

The little boy pleaded with his relatives to take him back to the Newburgh dock, where a makeshift memorial for his loved ones continues to grow.

"He said, 'Auntie, take me to the water,'" Angie Gilliam said of her nephew.

"He wanted to go," Gilliam told the Daily News. "He just looked. I gave him his time and he did what he needed to do. He did a big thing there to get out."

Lashaun looked at the balloons, stuffed animals and flowers left by mourners at the dock. But mostly he stared at the water.