the resolution, if it happens, will not be a not guilty by reason of insanity acquittal,  he said.

6 Yates drowned her children in the bathtub of their home. Pictured above, from left to right, are four of her children, Luke, Paul, John and Noah. Getty Images

He predicts that she will likely be convicted of lesser charges and be incarcerated for  a short period of time,  although he believes that she should have been found not guilty by reason of insanity.

Parnham referenced Yates' case, in which a jury initially found her guilty instead of insane for drowning her children in the bathtub of her home just outside of Houston.

But the 2002 capital murder conviction was thrown out after it emerged that a forensic psychiatrist for the prosecution gave false testimony. A second jury found her not guilty by reason of insanity in 2006. Yates remains at Kerrville State Hospital for treatment.

6 Clancy's lawyer was disappointed with the mistrial.

 We came back, retried it and they acquitted her,  the lawyer said.

Yates' groundbreaking murder trial bears striking similarities to the Clancy case - in which the 36-year-old Massachusetts mother strangled her three children to death.

Both mothers said they suffered postpartum psychosis and neither had any  ulterior motives  for killing their children - such as money or revenge against the father, according to Parnham.

 You eliminate all the possibilities of ulterior motives and you end up with the undeniable fact that mental illness is the reason these situations occurred,  he said.

Yates was 37 on June 20, 2001, when she killed her children - Noah, 7, John, 5, Paul, 3, Luke, 2, and Mary, 6 months.

She waited for her husband, Rusty, to go to work before drowning them, one by one, then called 911, according to testimony.

6 Parnham, pictured in court with Yates, said the mistrial could be used to the defenses' advantage. AFP via Getty Images

 I've worked on a lot of capital murder cases but when a mother and child are involved, it's a totally different perspective,  he said.  Jurors are perplexed and astonished really. 

Clancy's attorney  has done an excellent job talking to jurors  about postpartum psychosis, which is extremely rare and hard to diagnose, he said.

Parnham, who still visits Yates every two months, said she's likely aware of Clancy's high-profile case, though they haven't discussed it.

He said Yates is making progress with her mental health, and has asked him to visit her kids' final resting places.

6 Yates killed her children inside of her family's home. Getty Images

 I'll go out and give flowers to the graves. She's so grateful that someone is doing that for her children,  he said.

He sometimes brings her food from Cracker Barrel, said she likes to read and is occasionally tasked with helping other patients.

 I love her like a daughter,  he said.

Clancy told her husband she heard a male voice telling her to  kill her children and kill herself,  a psychologist testified during the trial.

Prosecutors contend she was in control and knew right from wrong.

Clancy is due back in court on Sept. 29.