A young Brooklyn boy who vanished while walking home from a day camp in one of the safest parts of New York City was killed and dismembered by a stranger he had turned to for help after getting lost, police said Wednesday.

An intense search for the missing eight-year-old, Leiby Kletzky, ended early Wednesday morning with the gruesome discovery of pieces of his dismembered body inside the home of a man who had been seen with the child around the time he disappeared, police said.

Police Commissioner Raymond Kelly said the 35-year-old suspect, Levi Aron, made statements implicating himself in the boy's death.

Investigators tracked Aron with the help of surveillance video that showed him being approached by the lost boy.

When detectives arrived at the man's home, they asked him where the boy was and he nodded toward the kitchen, Kelly said.

Detectives saw blood on the freezer door and they opened it to discover bloody knives, a cutting board and feet inside, according to a law enforcement official who spoke to The Associated Press on condition of anonymity because the investigation is ongoing.

Additional body parts were found inside a red suitcase that had been tossed into a trash bin in another Brooklyn neighbourhood.

Investigators focused on surveillance video

Police and volunteers had been looking since late Monday afternoon for Leiby, who disappeared while on his way to meet his mother in the Orthodox Jewish neighbourhood of Borough Park.

The break in the case came when investigators focused on a grainy surveillance video that showed the boy, wearing his backpack, walking down the street, while a man walked nearby.

Detectives noticed the man on the video going into a nearby dentist's office, Browne said. The dentist, located later in New Jersey, said he remembered someone coming by to pay a bill for a patient, and police were able to identify Aron using records from the office. When they went to his home, they made the gruesome discovery.

Police said Aron lives alone in the apartment, in a building shared with his parents. He once had a summons for urinating in public but otherwise did not have a criminal record, Kelly said.

Outside the family's apartment building Wednesday morning, men and women from the community clustered in separate groups. Many of the mothers gathered there said the streets are safe enough for a child Leiby's age to walk home alone.

"This is a no-crime area," said state assemblyman Dov Hikind, whose district includes the area. He said the boy was the only son of the Kletzky family. The couple have four daughters, and the husband works as a driver for a private car service.

'Everyone is in total shock'

"Everybody is absolutely horrified," he said. "Everyone is in total shock, beyond belief, beyond comprehension … to suddenly disappear and then the details … and the fact someone in the extended community … it's awful," he said.

He said the parents did not know Aron, who lived about 1½ kilometres away from the boy.

At about 6:45 a.m., an NYPD crime unit carted away the trash bin where some of the body parts had been found and put it in a truck, and police officers walked in a line looking for evidence under cars and on sidewalks.

The medical examiner's office will determine a cause of death and positive identification.

Leiby was one of the neighbourhood's many Hasidic Jews, an ultra-Orthodox people who live in tight-knit, somewhat insular communities and abide by strict religious rules that require men to wear dark clothing that includes a long coat and a fedora-type hat. Men often have long beards and earlocks.

Most of the 165,000 members in the New York City the area live in neighbourhoods in Brooklyn and are part of three different sects. Hasidism traces its roots to 18th-century Eastern Europe.

A $100,000 reward had been offered, and Hikind said the outpouring of support had been tremendous with people from all over the state volunteering their time to scour the neighbourhood and hand out flyers.

Adel Erps, who lives two blocks from the family, said she was very upset because the state of the body means it will be more difficult to do a proper burial. Like other neighbourhood residents congregating near the boy's home Wednesday, she expressed shock that the suspect was Jewish.

"He's a sick person obviously, but it hurts so much more," she said.