Texas Man Who Beheaded 3 Kids Over 'Demonic Possession' Set to Be Executed

John Allen Rubio is set to be executed for the murders of his 3 children, whose decapitated bodies were discovered inside the family's Texas apartment.

According to reports, John killed his 3-year-old Julissa Quesada, 14-month-old John E. Rubio, and 2-month-old Mary Jane Rubio

In an on-camera interview with KRGV, Rubio claimed he had been witnessing bizarre things in the days leading up to the murders, which convinced him someone was practicing witchcraft against his family.

But things took an even darker turn on March 11, 2003, when Rubio claimed his 3-year-old daughter Julissa began acting strangely.

According to Rubio, Julissa started claiming she was his grandmother ... something he said was particularly disturbing because he'd previously dreamed his daughter was possessed by his grandmother.

The children were killed and decapitated inside the family's apartment.

The following day, Rubio said his brother found the children's bodies inside plastic bags placed beside the beds ... and called cops.

Camacho gave three different accounts of why the children were killed. In one, she claimed the couple believed the children were possessed. In another, she said they couldn't afford to raise them. A third account suggested both financial struggles and their beliefs about possession played a role.

Prosecutors didn't buy his claims.

Cameron County District Attorney Luis V. Saenz described the murders as the worst case he'd ever encountered in his career.

The case has now gone through two trials ... and Rubio has been convicted twice.

Rubio was originally convicted and sentenced to death in 2003, but an appeals court overturned that conviction in 2007. He was retried and convicted again on August 2, 2010, receiving another death sentence.

Camacho pleaded guilty to three counts of capital murder in 2005 and is currently serving a life sentence. She will be eligible for parole in 2043.

Now, more than two decades after the murders, Rubio is facing execution ... and he says he's ready to die.

"Now that I have an execution date, I'm ready to be with my children, I'm ready to be with God. I know they know the truth; I adored my children," Rubio said.