SUNSET PARK, Brooklyn (PIX11) — A mother was killed and her two kids were left fighting for their lives after they were attacked with a hammer on Wednesday in their Brooklyn apartment, according to police.

A call came in around 1:50 p.m. for an assault on 52nd Street in Sunset Park, police said. The mother, identified by police as 43-year-old Zhao Zhao, died from her injuries.

NYPD officials said her 5-year-old son and 3-year-old daughter were both fighting for their lives in the hospital. They remained in critical condition, as of Thursday morning.

When police arrived, they placed 47-year-old Liyong Ye in custody as he was leaving the building covered in blood, an NYPD official said. Upon entering the second-floor apartment, they found the victims all suffering from trauma to the head.

Police said the illegally subdivided three-bedroom home was being shared by three families — the victim and her two kids and the suspect and his 9-year-old son, along with the suspect’s younger brother.

“They’re arguments, they were pretty intense, and apparently it was intense enough for him to pick up a hammer and bash them in the head,” said Stephanie Dong, who lives in the building.

Dong said she couldn’t help but hear the fighting over the last few days between the mother who was killed and the man who allegedly did it.

“You had to be worried because it was really intense, and you didn’t know what was gonna go on, but it wasn’t your business, so you didn’t call the police, but maybe you should have,” Dong told PIX11 News.

Dong said the brothers worked as delivery drivers and the arguments were over noise.

“Apparently, the woman, she didn’t like that these guys. They were coming home late; they were disturbing them. She kept asking them to be quiet right, but they wouldn’t,” Dong said.

That’s what led up to the attack, Dong said. The suspect had reportedly told his brother — who wasn’t home — to call 911.

“They say he wasn’t really that stable. He looked normal, but he was unstable in the mind,” said Dong.

Both the suspect and victim are Fujianese, part of a tight-knit local community.

Ye was charged with murder and attempted murder, police said.