When firefighters forced their way inside, they found a one-year-old girl with her wrists and ankles bound together, according to the arrest affidavit; she had a black eye and a bloodied lip.
A two year-old boy wearing a "heavily soiled" diaper meanwhile was trapped inside a playpen "that was completely covered" by a changing table and a baby carrier, KSAT reported.
According to the affidavit, Salais had temporary custody of the children because their biological parents are being investigated by Child Protective Services due to concerns of physical abuse.
It is unclear how Salais was given custody; according to a CPS representative, she is not a licensed foster care parent in the state of Texas. Per the Department of Family and Protective Services, whenever a child is placed with a guardian, they must pass a background check and have a judge's approval.
According to the outlet, Salais has faced a number of criminal charges — including aggravated assault with a deadly weapon — dating back to 2002; however all charges were dismissed through a combination of deferred adjudication, insufficient evidence or missing witnesses.
As she was being taken into custody, Salais protested her innocence.
"Y'all truly need to get y'alls facts straight," she told a WOAI reporter. "Y'all are releasing bulls---. Talk to my grandma."
According to the children's mother Isabella, Salais is her stepmother, and the children's step-grandmother.
"You have to be really sick in your head to do something like that somebody's children especially to a one-year-old and a two-year-old."
Isabella claims CPS had taken the kids from her after deeming her "an inherent risk", previously placing them in foster care.
"All the risks that were supposedly at risk being with me their mother is exactly what happened in the homes that they put them in," she said. "My daughter was found tied up to a playpen, and my son was found inside of a playpen with the cover on it pretty much and the door was locked, and fire people had to kick open the bedroom door, where they also then found my kids tied like that."
To her children, she added: "Tell them that I’m sorry, I'm sorry that it got this far and that I should never have trusted anybody with them. And that I just want them to come home already."
But according to Salais' father Billy, his daughter would never hurt a child; he insisted she was helping Isabella watch the children, and that someone else was responsible for harming them.
"The kids she's taken into her home out of the kindness of her heart is because that's the kind of person she is," he told KSAT. "Now this sensationalized version that's being portrayed on her is totally inaccurate."
If Salais is found guilty of child endangerment, she faces a maximum prison sentence of two years — which according to San Antonio Police Chief William McManus isn't quite enough.
"What she did to these children is, I mean, it's unforgivable," he said. "Two years seems like nothing compared to what she did to these children."
While Isabella insists she didn't know her children were being hogtied, Chief McManus said he hoped — for her sake — that was true.
"The children were taken from her. So, I don't know what kind of connection she had by law after that happened," he said. "So, I can't comment on that."
Salais is being held on $150k bond; $75k for each child.
The children are now back in the care of the CPS; police also found a five-month-old sibling, safe, at a different home.