Texas Man Who Beheaded His 3 Children Executed After Telling Crowd He'll See Kids 'Soon'

John Allen Rubio was executed for the murders of his 3 children last night ... after eerily telling the crowd watching him being put to death that he would see them soon in heaven.

Rubio was given a lethal injection Thursday night in his Huntsville prison ... AP News reported.

Before he was put to death, he said ... "I’m going to be with my kids in a little bit. I’m ready to go to heaven to be with my lord and savior."

Rubio also apologized to his wife's family, saying ... "I can’t change the past but I can tell you my life is going to be over. But that’s not going to make you happy."

Rubio was convicted of murdering his children -- 3-year-old Julissa Quesada, 14-month-old John E. Rubio, and 2-month-old Mary Jane Rubio. Their bodies were found beheaded inside plastic bags in March 2003.

At the time ... Rubio claimed Julissa had said that she was his grandmother ... and that he previously had a dream where she was possessed by his grandmother.

Rubio's wife, Angela Camacho, changed her tune frequently about why their kids were murdered ... from blaming Camacho and Rubio's belief that they were possessed, to not having enough money to raise them, to a combo of the two.

Rubio's original murder conviction and death sentence were overturned in 2007 ... before he was retried and given the same sentence in 2010.