The body of Sherin Mathews was found on Sunday in a culvert under a road nearly 1 km from her home.
Wesley Mathews, the foster father of Sherin was re-arrested after he changed his story about his daughter's mysterious disappearance on October 7 from their home.
Lawyers Michelle Nolte and Gregg Gibbs, representing Sini Mathews issued a statement on Wednesday saying she denied any involvement in the death of her adoptive daughter, Sherin.
In the statement, the lawyers said Sini has cooperated with the police investigation into her daughter's disappearance on October 7 from their home in Richardson.
She was ‘interrogated for hours by several officers with no attorney present’ a few days later.
‘Now that Mr Mathews has turned himself into the police and told them what happened to Sherin, we see no need for Mrs Mathews to endure further police interrogation. She had nothing to do with Sherin's death or the removal of her body from the home,’ the statement said.
According to court records, Wesley previously told detectives his wife was sleeping when Sherin disappeared.
On Wednesday, Wesley was transferred to the Lew Sterrett Justice Center, where he will be under the custody of the Dallas County Sheriff's Department, Richardson Police Department said.
It said that detectives were gathering evidence in the death of Sherin Mathews.
US media reported that the 37-year-old Indian-American, who worked in an IT company, has been placed under suicide watch.
Wesley Mathews is currently charged with injury to a child, a first degree felony and his bond is set at $1 million.
The lawyers of Sini Mathews said she is ‘trying to grieve for her lost daughter while still caring for her remaining daughter. She is struggling to pick up the pieces of a shattered life’.
Richardson Police had no immediate comment to the statement by Sini, a registered nurse.
The police previously said Sini initially cooperated in the investigation on October 7, but then stopped. This week, police said she provided the dental records and identified clothing found with Sherin’s body to help the medical examiner make a positive identification.
Police also said that Sini never provided a full account of what happened when Sherin died.
Wesley Mathews is the only person charged with a crime in Sherin's disappearance and death.
Mathews originally told police his daughter Sherin disappeared while being punished, when she was forced to stand outside by a tree at 3 am for not drinking her milk.
Later when the body was found, he changed his story and said that his daughter choked to death after he ‘physically assisted’ her in drinking her milk.
Meanwhile, a petition has been started by community leader Father Thomas Ambalaveli to not hand over the body of Sherin to her parents, and rather to the community, so that a proper memorial and burial service could be done.
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