Haunting new video revealed the terrifying moment a homeless ex-con allegedly fatally stabbed a 23-year-old Ukrainian refugee in what police said was a random attack on a North Carolina light rail train.

Iryna Zarutska, who fled war-torn Ukraine for a safer life in America, was on the Lynx Blue Line in Charlotte just before 10 p.m. Aug. 22 when she was ambushed, according to the Charlotte-Mecklenburg Police Department.

The surveillance footage, released Friday by the Charlotte Area Transit System (CATS), shows Zarutska boarding the train in her pizzeria uniform at 9:46 p.m. and sitting, looking at her phone, unaware of the danger behind her.

Just four minutes later, 34-year-old Decarlos Brown Jr. allegedly whips out a folding knife and lunges forward, stabbing her three times, at least once in the neck, police said.

The chilling video then appears to show Brown walking through the rail car, stripping off his sweatshirt and waiting by the doors — as passengers began to notice blood dripping from him.

Zarutska, who grabbed her neck as blood spilled onto the train floor, collapsed in her seat and was pronounced dead on the light rail, investigators said.

Police said Brown got off at the next stop, where a folding knife was later recovered near the platform. He was treated at a hospital for a cut on his hand before being taken into custody on a murder charge.

It took six minutes for police to respond, according to Spectrum News, which noted transit security guards were on the train, but in the car ahead of Zarutska’s when she was attacked.

Brown — who has multiple arrests dating back to 2011 — was charged with first-degree murder, according to CMPD. His record includes larceny, robbery with a dangerous weapon and communicating threats, according to court records obtained by The Post.

The suspect is homeless and once served five years in prison for robbery with a deadly weapon, according to WSOC-TV.

In January, Brown was arrested and charged with misusing 911 after a police welfare check, the Charlotte Observer reported. 

During that incident, officers said, he bizarrely claimed a “man-made” material inside his body was controlling him as he ate, walked and talked, according to an affidavit cited by the outlet.

“Brown wanted officers to investigate this ‘man-made’ material that was inside of his body,” the affidavit said.

CATS officials said during a Sept. 2 public transit meeting they have since hired a chief safety and security officer, tripled the safety budget and begun replacing aging cameras with high-tech upgrades. 

On Sept. 22, the Charlotte City Council will consider a plan to expand Charlotte-Mecklenburg police patrols on buses and trains. CATS officials also said Friday the video was released due to media requests.

A GoFundMe set up by Zarutska’s family, which has raised more than $38,000 so far, said she had “recently arrived in the United States, seeking safety from the war and hoping for a new beginning.”

“Tragically, her life was cut short far too soon,” the fundraiser read.

The investigation remains ongoing as police continue to search for a motive.