NEWBURGH, N.Y. (CBSNewYork) -- Newburgh authorities believe Lashandra Armstrong of Orange County killed herself and three of her children by driving her minivan into the Hudson River Tuesday night.
Officials say that Armstrong, 25, had all four of her children in the minivan when she drove it into the murky depths of the Hudson River. However, one child -- 10-year-old Lashaun Armstrong -- managed to escape by slipping out of the van before it sank below the waves.
Police announced Wednesday the apparent murder-suicide took place after Armstrong was involved in a domestic dispute. Armstrong had apparently found out that her husband had been cheating on her and was distraught.
WCBS 880's Sean Adams With Reaction From Mayor Nick Valentine
"He managed to hit the power windows and opened up one of the windows and climbed out of the vehicle before the vehicle sunk," said Chief Mike Ferrara of the Newburgh Police Department, describing how Lashaun Armstrong escaped.
The boy swam back to the shore. Maeve Ryan, a passerby, found the soaking wet, shivering boy and took him to firefighters, authorities said.
Wednesday night Ryan told CBS 2's Sean Hennessey "I don't know what state of mind she could have been in to do that to her children."
Ryan said that she "will never forget [Lashaun's] face because the fear in that little boy's eyes was just terrible." The lone survivor of the tragedy told Ryan that before they went into the water, his mother went into the back seat and held the kids and said "if we're going to die, we're going to die together."
Fire officials said the boy probably had less than two minutes to escape.
WCBS 880's Sean Adams: Aunt Among Those Searching For Answers
Armstrong's aunt, Angela Gilliam, was at the scene of the horrific tragedy Wednesday in tears, asking "why would she drive her car down there?"
Gilliam told police she spoke with her niece earlier Tuesday and that Armstrong was "not too good."
CBS 2's Pablo Guzman asked Gilliam how her nephew was feeling a night after his mother and siblings drowned.
"He's taking it easy," an emotional Gilliam said, "he had the strength to get out and try to get help. Lashaun is fine."
Lashaun told authorities his mother had just driven into the river with his brothers and sister. He may have been suffering some hypothermia from the approximately 45-degree waters when he told them about his escape.
"When Lashaun came to the fire department, he was having difficulty speaking, of course, and was just repeating about the car being in the water with him mom and siblings," said Chief Michael Vatter of the Newburgh Fire Department.
Police boats and divers pulled the minivan from the Hudson late Wednesday night.
Two boys, five-year-old Pierce Armstrong, two-year-old Lance Pierre and their 11-month-old sister Lainina were drowned along with their mother.
1010 WINS' Kathleen Maloney reports: Nightmare In Newburgh
"I don't know her. Like I said, I have nine grandchildren of my own and I can't imagine, I just can't imagine," said Delores Currier of New Windsor.
"We are talking about a tragedy in this city that is probably second to none," Newburgh Mayor Nicholas Valentine said. "The whole scene surrounding what occurred in Newburgh last night will have a lasting effect on this city," he added.
Police had been responding to a domestic dispute call at the Armstrong's home about six blocks away from the river when they got word.
Officers arrived to find an empty house, and minutes later, Lashaun was delivered to the firehouse.
1010 WINS' Terry Sheridan reports: Neighbors Are Shocked
Armstrong's neighbors on Williams Street have expressed shock.
"I just know that she works, and she goes to school... she was always out with the kids, playing. It's amazing," said Carmen Davila. "She seemed like a real busy person and real responsible with those kids."
Other neighbors said they were not aware of any problems in the household.
"If there was something going on nobody would've known because we never heard anything, she never said nothing to nobody, they're very quiet people," neighbor Tina Claybourne said. "We never heard no violence, no screaming, no nothing."
for more features.