After looking into the case, prosecutors added more charges and indicted the couple in late November.
WSB-TV first reported that court records accuse Lewis of being the main culprit, forcing his stepdaughter to stand barefoot on tin cans while writing out what he called "standards" on a piece of paper.
"Which would be a sentence that he would require her to write, like, ‘I will respect my father,’ 1,000 times. This happened almost on a daily basis," said prosecutor Tracie Cason.
Cason said the teenager was beaten and starved as well.
"There were times she was only allowed to eat cat food, and there were times she wasn't allowed to eat at all until the defendant decided she could eat," Cason said.
Investigators say the girl was locked in a laundry room for extended periods of time -- so long that she urinated and defecated on herself.
The indictment also says Lewis abused the girl "by telling the child to stop stuttering" and "pushing his thumbs into the mouth of (victim) with such force as to split the corners of her mouth and with such severity to leave scarring to both corners of her mouth."
Prosecutors also say the girl was forced to take baths in either extremely hot or cold water, and either peroxide or lemon juice was added.
Counselors at the girl’s middle school became concerned earlier this year and called police.
Gwinnett County police charged Lewis and Strothers each with one count of abuse, but prosecutors said, as they looked into the case, they realized it was much worse than was first believed and that the abuse had apparently gone on for years.
"It's amazing to me how this child survived as long as she did," Cason said.
Records show Lewis has been in trouble for similar actions before.
Authorities said he entered into a negotiated guilty plea in 2014 for abuse surrounding the same girl. He was given credit for time served and put on probation.
These most recent charges are a violation of that probation, according to prosecutors, so Lewis was sentenced this summer to five years in prison. The girl's mother remains out on bond.
"It's our understanding they moved from Cobb County to Gwinnett County to avoid DFCS's attention," Cason said.
Prosecutors said while Strothers didn't necessarily directly cause any of the abuse, she knew of the starvation and beatings.
They also accuse her of reporting to her husband when the child would not follow his rules.
Authorities said in the short time between when Lewis was charged with these latest crimes and when he was sent to prison, he violated a judge's order not to have any contact with his stepdaughter.
Investigators said, through his wife, he bought the girl clothes, told her he was sorry for what had happened and promised there would be no abuse in the future.
That got him an added charge of stalking from the grand jury.
"It's hard enough to just try and take care of a child, but abusing one? You’re making your job harder," said former neighbor Wesley Jacobs.
Lewis' attorney of record did not reply to requests for comment. Records do not show an attorney for Angela Strothers.