Following charges being dropped against a Chattanooga woman who tested positive for drugs while pregnant with her now-dead infant children, a criminal defense attorney with no connection to Tiffany Roberts is weighing in on the case.

The Hamilton County District Attorney's Office released a statement Thursday announcing the decision to drop First Degree Murder and Aggravated Child Abuse charges against Roberts.

Despite Roberts admitting to using several narcotics during her pregnancy, the charges were dropped due to the medical examiner's early findings.

"That's reasonable doubt," Criminal Defense Attorney Robin Flores told Channel 3. "In the criminal homicide statute, there's a definition of a fetus as a viable victim."

According to the DA's office, the medical examiner's preliminary report stated the children's death could not be solely linked to Roberts's drug use.

"If you can't establish beyond a reasonable doubt the mechanism of death and the mens rea (defined as the intention or knowledge of wrongdoing that constitutes part of a crime), then the state's case will fail," Flores explained.

He says the seriousness of the charges and the burden of proving first-degree murder, made it difficult for state prosecutors to make their case.

"The standard is much tougher because you have to show premeditation. That's the only statute in the Tennessee code that requires premeditation," Flores continued.

According to court documents, Roberts tested positive for cocaine, oxycodone, meth and other drugs while pregnant and so did her children.

An affidavit states that she told investigators she knew she had a problem.

"The medical examiner's report was so grey that the state wouldn't be able to meet that high, high burden. I could see why the dismissed the case," Flores said.

The DA's statement Thursday said state law would not have supported prosecuting the case based on the medical examiner's preliminary findings.

We asked Flores if he believed there was any chance Roberts could face charges later.

He says there's no statute of limitation on First Degree Murder and they're within the timeline for Second Degree Murder.

However, the outcome would depend on whether prosecutors could prove Roberts killed her children deliberately and whether their death could be solely linked to her alleged drug use.