A St. Louis man was shocked to discover a dead baby in his mother's freezer as he cleaned out her home after she died.

Adam Smith told NBC affiliate KSDK he had moved into his mother’s home in Missouri as she was battling cancer, to help care for her in her final days.

When she passed away, he started going through her stuff, sorting out what to keep and what to toss. He remembered a box that had been in his mother’s freezer his whole life. He was told never to open it.

“I'm 37 and it has been in my freezer for 37 years. I was always told it was a wedding cake top," Smith told KSDK.

But when he opened it, Smith found a frozen baby, wrapped in pink fleece.

“It still had skin, hair and everything,” Smith said. “It was mummified.”

Smith said his mother had mentioned she had lost a child before he was born, but he said she was a secretive person who would not speak more on the subject.

Smith called the St. Louis Metropolitan Police, who told NBC News they are investigating the case as a "suspicious death" and that the child abuse and homicide departments responded to Smith's call.

Smith also reached out to his estranged father about the discovery, according to the St. Louis Post-Dispatch.

“He told me my mom was pregnant on their first date and that the next time he saw her, she wasn’t,” he said.

Smith said he is confused and upset and that the discovery has made grieving for his mother more difficult.

“I want more answers,” he added.