Editor's Note: Some of the details in this story are graphic and may be upsetting to readers.
We've learned new details about the case of a Sperry couple accused of torturing their four adopted children.
The first two arrests came in March 2012, when two parents were charged with abusing their adopted kids. Now, the couple's biological son is accused of preying on the same four children.
Investigators say four children endured heinous physical and sexual abuse at the hands of their adoptive mother and father inside their Sperry home. Aubrey and Lora Lee Thomas were arrested nearly two years ago.
Now, investigators say the couple's biological son was also in on the abuse.
An affidavit says Garrett Thomas, who is now 23, was using the children for his own sexual gratification.
The children claim their adoptive brother forced them to play a game which involved them touching his anus.
An affidavit says Garrett admitted to abusing his adoptive siblings five times when he was 18. He also told investigators he would make the children play "patty cake" with his naked butt.
Investigators say, while all that was going on, the children were being subjected to even worse torture by their parents.
The children's allegations include being forced to eat gum off of Aubrey Thomas' penis, forced to perform oral sex on their siblings for food, forced to put urine soaked panties in their mouth if they wet the bed, forced to eat their vomit and as punishment for not cleaning a horse pen, they say they were forced to eat horse manure.
Aubrey and Lora Lee Thomas are still awaiting trial. Aubrey Thomas is charged with three counts of child abuse and one count of enabling child abuse. Lora Lee Thomas is charged with four counts of child abuse.
Garrett Thomas was arrested in Rogers County on Christmas Eve. He's expected to be transferred to Osage County sometime Friday.
A jury trial for his parents is scheduled to begin next Tuesday.