By Matt Goodman and L.P. Phillips,

DALLAS (CBSDFW.COM)  – The 34-year-old father accused of starving his 11-year-old child to death has a history of limiting food to his family as a form of punishment, the boy’s biological mother said Monday.

Dallas Police on Saturday charged Aaron Ramsey, 34, and his wife Elizabeth Ramsey, 31, with injury to a child. Investigators believe they deprived 11-year-old Johnathan Ramsey of food until he died and then left his body in a wooded area south of Ennis between six months and a year ago.

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Police have not recovered the body, but said charges may be upgraded if Johnathan’s remains are found.

The boy’s biological mother told 1080 KRLD on Monday that Aaron Ramsey began acting strangely after he returned home from serving in the military in Iraq eight years ago.

“When me and him were living with his mom he was starting to do that to the rest of us; sort of, with just eating rice and beans,” said Judy Williams, Aaron Ramsey’s ex-wife and Johnathan’s mother.

Williams and Aaron Ramsey divorced in 2007, court records show. After returning from overseas eight years ago, Williams said her husband wasn’t himself.

“I can’t really describe his behavior, it was bizarre,” she said. “He became very controlling, just different,” she said. “I can’t really explain it too much, he just wasn’t the same. He had anger issues, I know that.”

Williams and Aaron Ramsey have another child named Eric who is 8 years old. Williams has custody of that child and was fighting for visitation rights of Johnathan, her stepmother Starla Swanson said.

Williams, who now lives near Albuquerque, N.M., said the last time she spoke to Johnathan was in January of 2011. She said the Ramseys “always had an excuse of why he couldn’t come to the phone.”

Investigators said they launched an investigation when the boy’s grandfather reported to Dallas Police that he hadn’t seen his grandson in nine months to a year.

In January 2011, Williams said her ex-husband changed both his mailing address and phone number.

“I had no recent phone numbers, I had no recent address, I had no idea where the kid was even living at,” she said. “I had no way of knowing where he was.”

According to police records obtained by CBS 11, Aaron Ramsey told investigators that his son exhibited violent behavior that peaked with him punching his pregnant stepmother in the stomach, causing her to miscarry triplets.

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He said he and his wife locked the boy inside his room and began feeding him “military rations” consisting of bread, water and occasionally milk. The police documents say the boy weighed 90 pounds in March and was 60 pounds at the time of his death.

Elizabeth Ramsey told investigators she saw the boy “eat his own feces” and later found him on the floor unresponsive and foaming from the mouth. She said they gave Johnathan a bath then “put on his favorite T-shirt and pants on and put him in a sleeping bag.”

The arrest warrant says the Ramseys then took the boy to a storm shelter next door to a vacant house and left him there for “one or two days” before dumping him in the area south of Ennis.

During the interview Monday, Williams rebuffed the idea that her son was violent and said there is no excuse for what her ex-husband and his wife are accused of doing.

“Saying he was violent? I’m sorry, I do not believe that unless he was provoked,” Williams said. “There’s no way he could’ve been violent –– I don’t believe that.”

Over the weekend, a neighbor said that she had seen the boy in the Ramseys’ backyard. She said she thought he looked unhealthy.

“His little arms were just thin. You know, too thin for a 10-year-old child,” said Rita Woodruff, whose house backs up to the Ramseys’.

Williams said she is saddened and enraged by what happened to her son. She said she can’t fathom the details behind the Ramseys’ charges.

“How dare you do this to my child, you know? Why couldn’t you just email me or call me, because you had my phone number, and say, ‘Hey, we can’t handle him, come and get him,’ or, ‘We’re going to send him to you,’” Williams said. “Why couldn’t you just call me and tell me?”

Aaron Ramsey and Elizabeth Ramsey are being held in the Dallas County Jail on $500,000 bond each.

CBS 11’s Andrea Lucia and Sharrie Williams contributed to this report.

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