The body of a 9-year-old boy was found at the edge of a waterway after he was separated from his family at an Ikea store in Red Hook, a neighborhood in Brooklyn, police say.

A law enforcement official confirmed to CNN that the boy had autism.

The child was seen on Ikea's surveillance video exiting the store just before 9 p.m. ET on Wednesday and walking towards the Erie Basin, a man-made protected harbor located behind the store, according to police.

The New York City Police Department and Fire Department of the City of New York responded to the pier behind Ikea and deployed patrol officers, aviation units, harbor units, the Technical Assistance Response Unit, K-9s and divers to find the child, police said.

The child's body was found several hours later, just after midnight on Thursday, at the water's edge behind Ikea, according to police. He was transported to New York Presbyterian/Brooklyn Methodist Hospital where he was pronounced dead.

"We at IKEA are devastated by this tragedy. Our hearts are with the family at this difficult time," a spokesperson from Ikea told CNN.

"I am heartbroken to hear the news of the 9-year-old child who drowned in Red Hook last night," New York City Councilmember Alexa Avilés told CNN. "As a mother and representative of this community, I extend my sincerest condolences to the family."

CNN has reached out to the New York City Medical Examiner's Office, which has not yet released the cause of death.

CNN has also reached out to the New York Presbyterian/Brooklyn Methodist Hospital for comment.