Discuss as:

Toddler's remains found buried in Long Island backyard

Police have discovered what they believe to be the remains of Justin Kowalczik, a missing 17-month-old boy in Farmingdale, Long Island.

According to investigators, Kowalczik's remains were found buried in the backyard of the home Justin's mother, Heather Kowalczik, rented with her boyfriend and their two other children.

The search for Justin was ignited Wednesday after police say someone called Child Protective Services out of concern for the health and welfare of Justin's 6-year-old sibling.

Police said when officials inquired into Justin's whereabouts, his mother first said he was with relatives, but then revealed he died in 2010. It was unclear how he died and why he was buried in the family's backyard.

Kowalczik and her boyfriend, Robert Rodriguez, have been questioned by police but have not been charged. An investigation is ongoing.

"It is absolutely a suspicious death and it is being investigated as such," said State Police Maj. Patrick Regan. "We don't have a cause of death, and to our knowledge, there was never a report made of the child being missing."

Also at NBCNewYork.com: Tour bus overturns

On Friday, an Amber Alert was issued when Rodriguez abducted his 9-year-old son, after allegedly learning of the investigation.

The Amber Alert was canceled a short while later when the two were found by police.

A medical examiner is performing an autopsy on Justin, who would have been 3 years old.

Police say Kowalczik and Rodriguez are no longer cooperating with authorities. Their two surviving children were in the custody of county child welfare agents, police said.
 
Neighbor Tekiera McCormack told Newsday that she was stunned.
 
"I can't see this," she told the newspaper. "This is crazy. She was a good mother. Those kids loved her."

Get the latest from NBC 4 New York anywhere, anytimeiPhone/iPad App | SMS AlertsTwitter | Facebook | Google+ | Instagram | RSS

More content from NBCNews.com:

Follow US news from NBCNews.com on Twitter and Facebook