NEW YORK - A Chinese immigrant who neighbors said struggled to survive in America was arrested Sunday on five counts of murder in the stabbing deaths of his cousin's wife and her four children in their Brooklyn home - using a butcher knife.

Mingdong Chen, 25, implicated himself in the killings late Saturday, police said.

"They were cut and butchered with a kitchen knife," said Department Chief Philip Banks III.

Linda Zhuo, 9, and Amy Zhuo, 7, were pronounced dead at the scene, along with William Zhuo, 1 - all attacked in a back bedroom, police said. Their brother Kevin Zhuo, 5, and mother, Qiao Zhen Li, 37, were taken to hospitals, where they were pronounced dead.

Chen is a cousin of the children's father and had been staying at the home for a week or so, Banks said.

Chen came to the United States from China in 2004, the chief said, but neighbors say he could never hold down a job.

"He made a very soft comment that since he came to this country, everybody seems to be doing better than him," the chief said. "We're not really sure what that means."

The chief said Chen still speaks only Mandarin Chinese despite being in the United States for almost a decade.

On Saturday night, Chen apparently had been acting in a "suspicious" way that concerned Li, Banks said. She tried to call her husband, who wasn't home, but couldn't reach him.

Banks said Li then called her mother-in-law in China, who also was unsuccessful in reaching her son. The mother-in-law reached out to her daughter in the same Brooklyn neighborhood, Banks said.

She and her husband went to the house and banged on the door. When it opened, they saw a man they didn't know, covered with blood. The couple called 911.