A mother in Miami, US, sparked an search for her 9-year-old autistic son after claiming "two black men" had abducted him.
She has now been charged with the boy's murder.
Prosecutors say Patricia Ripley pushed her son Alejandro into the lake to drown him.
They claim she had tried to drown him earlier in the same evening but a passer-by had rescued him.
Alejandro, who was non-verbal, died on Thursday night.
That same night, his mum called police to claim a car had followed hers while she was driving at 8.30pm, then sideswiped her and forced her off the road. According to her story, one of the men blocked her in while another one jumped out with a knife and demanded drugs.
"She says she does not have any drugs. And so the passenger reaches in, grabs her cell phone, steals her cell phone, and takes her child," Miami-Dade Detective Angel Rodriguez said.
Alejandro's body was found on Friday morning, floating in a lake not far from where he had supposedly been abducted.
Authorities found he had suffered head trauma and surveillance footage shows the mother pulling into the carpark and waiting 15 minutes before reporting the alleged abduction to police.
According to detectives, Ripley broke down when they told her witnesses had seen her near the lake with her son.
Police then reportedly found video showing her pushing the boy into a canal at 7.30pm, but he was later rescued by a passer-by.
Prosecutors say that, one hour later, she pushed him back in - this time, to his death.
She reportedly told police during her confession that "he is going to be in a better place".