“She believed that the child could possibly be deceased,” Spencer said.

About an hour later, police say they began to conduct surveillance on the home and saw Toseland and a woman leave the residence and get into a car. Toseland was immediately detained and the woman, who was identified as the kids’ mother, was interviewed.

Spencer said that the mother had not seen her 4-year-old since Dec. 11 and that Toseland, who was her boyfriend, had abused her and forbidden her from leaving the house or going into the garage. Police ultimately found a freezer in the garage that contained the young boy’s remains.

“We believe the child has been deceased since early December,” Spencer said. The lieutenant added that while authorities do not believe the children’s mother was involved in the young boy’s death, “there are a lot of questions that we still have to answer about what occurred over the last three months.”

“This is a tragic situation,” Spencer said, adding that the elementary school girl who brought the note to school was safe with other family members.

One Saddle Brook Park Drive neighbor, who did not wish to be identified for fear of personal retribution, told The Daily Beast that she was “shocked” to hear about the terrifying allegations made against Toseland. Calling the neighborhood “quiet,” the resident said she never “expected anything like this to happen here.”

In an interview with KTNV, however, family friend Alberta Amezcua described Toseland as “very aggressive.” “It’s heartbreaking,” she said. "What goes through people’s minds? He was such a happy kid."

During Toseland’s first court appearance in Las Vegas Justice Court, prosecutor Tim Fettig revealed that the child had “visible injuries.” The Clark County coroner’s office will release the child’s name and cause of death after an autopsy has been completed.

Toseland, who is not the father of either child, was originally charged with kidnapping and was rebooked into Clark County Detention Center on the murder charge on Wednesday afternoon. He is expected to have another court appearance Thursday morning.

It is not immediately clear if Toseland has retained an attorney, and his family did not immediately respond to The Daily Beast’s requests for comment.

Court records show that this is not Toseland’s first run-in with the law. Dating back to at least 2005, Toseland has been arrested several times in Las Vegas on a slew of charges, ranging from domestic battery to disorderly conduct.