Mother seeking answers after son was found dead in chimney of NYC school

Questions are mounting about the death of a man whose body was found in the chimney of a New York City public school.

Sophia Wood said she was supposed to meet her 29-year-old son, Matthew Collado, back on May 10 for Mother's Day, but he never showed up.

"I sent him a text, like, 'Hello?' Which meant I was annoyed because why am I texting you on Mother's Day? You're supposed to be calling me first, right?" Wood said. "I didn't make a big deal about it. I just figured just I'm gonna go home and I'm gonna trust that he's fine."

Wood says a search at her son's Jamaica apartment initially turned up his wallet and phone, but no Collado, leading his family to file a missing person's report on May 13.

Surveillance footage obtained by CBS News New York shows Collado leaving his apartment building just after 3 a.m. on May 9, the last time he would be seen.

"Why are you leaving the house at that time? What are you doing? What's going on?" Wood said.

Despite the family's tireless search efforts, weeks went by with no news.

A break in the case came in late June when police were called to P.S. 113 in Glendale, Queens, after an exterminator hired to investigate a foul odor inside the building made a gruesome discovery – human remains inside the school's chimney.

A series of tests over the course of three weeks resulted in the news Wood had been dreading.

"They said the dental records along with the pictures and the way I described him confirmed that it was Matthew that they found in the chimney," Wood said.

Weeks later, Wood says she's still processing it.

"It was hard because, like, why? Like, how, you know? How could this be him?" she said. "This is not the life I knew that my son lived."

Collado's family now consumed with questions in a case that his mother says makes little to no sense.

"It just all seems so uncharacteristic. It just all seems so strange," she said.

Police say the investigation is ongoing, and the medical examiner's office told CBS News New York the cause and manner of Collado's death are pending further study.

Collado's mother is now hoping someone who knows something comes forward.

"I feel like I'm being bamboozled. I feel like it's a freaking nightmare," she said. "It's a bad trick."