Cassie Smith has been charged with murdering her son. Photo / Supplied
The mother of a toddler who claimed her son had disappeared during a trip to a local park has been arrested.
The body of three-year-old Daniel Theriot was discovered near Lake Mead National Recreation Area in the early hours of Monday morning, after he was reported missing by his mother on Sunday morning, the Daily Mail reported.
Cassie Smith, 20, called 911 around 9am yesterday, telling police she'd taken her son to feed the ducks at Sunset Park,Las Vegas, but when she'd looked away for a second to use her phone, he'd disappeared.
Police immediately mounted a huge search effort, closing the park and checking each car as they left. But investigators say they also began to have their suspicions about the woman's version of events and launched a simultaneous criminal investigation.
Ray Spencer, a homicide detective, told a news conference on Monday that it didn't make sense for the mom to take Daniel to Sunset Park, a huge 300-acre space with a 9-acre lake, when they lived in walking distance of Lorenzi Park.
"It didn't make sense," he said.
He also said that no one at the park remembered seeing Daniel with his mom, or even noticed the woman frantically searching.
"We started doubting if the three-year-old was ever at the park," he said. "We suspected some foul play was involved."
At just before 5am on Monday, Daniel's body was discovered near Lake Mead National Recreation Area.
It appears that he was killed and dumped there up to 12 hours before his mother called to report him missing from the park.
Spencer also made clear there was 'nothing accidental about the death of the child.'
The mother and her 40-year-old boyfriend have now been arrested. Police will release their names later today.
Police also rescued a two-year-old child from their home that they say was another victim of child abuse. The child has been taken into care.
The pair will be charged with child abuse over the two-year-old later this afternoon and Spencer said they will be facing murder charges over the death of Daniel.
He added that the local Child Protective Services didn't appear to have any history with the family but there were some past criminal convictions.
Police had announced early Monday that they have called off the search efforts.
More than 30 volunteers were assembled to comb through the park, playground and parking lot, immediately after the missing persons report.
The team also searched the surrounding neighbourhood and railroad tracks, and handed out missing flyers to local people and businesses.