Sherin Mathews was killed with "homicidal violence" before her father tucked the 3-year-old's body into a Richardson culvert where it went undiscovered for weeks, an autopsy report shows.

As police and the public searched in October for the little girl many rightly feared was dead, her body decomposed, making it more difficult to determine how she died. Details of the autopsy results, including any more information about how Sherin died, were not immediately released.

Sherin Mathews

Ruling Sherin's death a homicide means that someone caused her death intentionally, knowingly or with criminal negligence.

Richardson police on Wednesday had filed no additional charges against her adoptive parents, who are already locked up in the Dallas County Jail. The department said Wednesday in a brief statement that it "is continuing to work with the Dallas County district attorney's office in pursuit of justice for Sherin."

The medical examiner's ruling is likely to help Dallas County prosecutors build a criminal case against Sherin's father, Wesley Mathews, who was arrested on a charge of injury to a child in October. The girl's mother, Sini Mathews, was arrested on a charge of child abandonment or endangerment in November. That charge stems from an allegation that the couple left Sherin alone the night before she died when they went to dinner with their biological daughter, now 4.

Wesley Mathews originally told police he left Sherin outside because she wouldn't drink milk and she disappeared. Police said he changed his story after her body was found on Oct. 24, saying he removed her body from the home after she choked on her milk. He put Sherin's body in his car with a bag of trash.

Wesley Mathews' attorney, Rafael de la Garza, could not be reached for comment. KXAS-TV (NBC5) reports that Sini Mathews' attorney said there is nothing in the autopsy or toxicology reports that would implicate her in Sherin's death.

The medical examiner's office has not released the autopsy report, saying it will seek a ruling from the attorney general's office on whether to make it public. Dallas County, in recent years, has routinely blocked the release of autopsy reports in homicide cases by saying the reports are part of an open investigation. Such reports were previously almost always public.

A custody hearing scheduled for Wednesday involving the Mathewses' surviving daughter was postponed.

The couple adopted Sherin from India in 2016. The family's Richardson home had many pictures of the biological daughter but none of Sherin.

Suspicions about Sherin's care had been raised before her death.

A doctor contacted CPS after finding multiple fractures in various stages of healing on Sherin in March. Sherin suffered injuries to her upper-arm bones and fractures in her leg bones that were in various stages of healing, according to court testimony.

Wesley and Sini Mathews both face charges in the death of their adopted daughter. (Dallas County Jail)

The doctor, Suzanne Dakil of the Referral and Evaluation of At Risk Children Clinic, testified at a November hearing involving custody of the couple's biological daughter that she suspected Sherin had been injured at the hands of her parents.

"I had no explanation other than this child had been physically abused," Dakil testified.

Sherin was also underweight, and Dakil treated that until the Mathewses stopped bringing her to the clinic after several months last year. Sherin also had a deformity in one eye at the time of her adoption.

Texas Child Protective Services Commissioner Hank Whitman said in November that Sherin's case "slipped through." He said he was disappointed in how the agency handled Sherin's case.

"I'm gonna tell you right now, it is my mission, it is my passion that we get better at this," he said.