If you or someone you know is having thoughts of suicide, please contact the National Suicide Prevention Lifeline at 988.

Lindsay Clancy, the Massachusetts mother accused of strangling her three young children with exercise bands earlier this year, pleaded not guilty Thursday to three counts of murder in connection with their deaths.

On Thursday, the 33-year-old was arraigned at Tewksbury Hospital on three counts of murder and strangulation after she was indicted in September in the deaths of her 5-year-old daughter, Cora, her 3-year-old son, Dawson, and her 8-month-old baby, Callan, before attempting suicide at her Duxbury home.

Lindsay Clancy with two of her three children in an undated photo. (Lindsay Marie Clancy/Facebook)

Kevin Reddington, Clancy’s attorney, argued that she was suffering with mental health issues and “was a troubled soul.”

LINDSAY CLANCY, MASSACHUSETTS MOTHER WHO STRANGLED HER 3 CHILDREN, RESEARCHED ‘WAYS TO KILL,’ COURT DOCS SAY

However, prosecutors pointed to recently unsealed 299 pages of records and argued that that Clancy’s alleged murders of her three children were deliberate and premeditated.

Lindsay Clancy holding one of her three children. (Courtesy: Lindsay Marie Clancy/Facebook)

According to the documents, unsealed by the Plymouth District Court, Clancy’s notebooks contained documentation of her medications and thoughts of suicide. 

Evidence collected through 11 search warrants from Clancy’s home also found that she used her cell phone to document her mental state and to research ways to kill.

TIMELINE OF LINDSAY CLANCY CASE

The judge presiding over Thursday’s hearing ordered Clancy to continue treatment for the next six months at the hospital, where she has been receiving treatment following her suicide attempt in January. 

Her next appearance is scheduled for Dec. 15.

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In the morning of Jan. 24, Clancy took her daughter to the pediatrician, called a local CVS store about a stool-softener prescription and ordered dinner at the ThreeV restaurant in Plymouth.

She also used Apple Maps on her phone “to determine the time it would take someone to travel from her home in Duxbury to ThreeV in Plymouth,” according to court documents.

MASSACHUSETTS MOM LINDSAY CLANCY’S 911 DISPATCH REVEALS FRANTIC FIRST RESPONDERS

Clancy also allegedly texted her husband to see if he could go and pick up the takeout at the restaurant and medication at CVS.

Lindsay Clancy’s home in Duxbury, Mass., where she allegedly killed her three children.  (David McGlynn for Fox News Digital)

When her husband, Patrick Clancy, arrived home, there was “silence,” court documents said.

Eventually, he found blood on the floor and noticed an open window.

According to court documents, he ran outside to the backyard, and found Lindsay on the ground, conscious and with cuts to her wrists and neck, and immediately called 911.

The father of the three children allegedly found his children in the basement.

Cora and Dawson were pronounced dead at the hospital on Jan. 24. 

Callan was flown to Boston Children’s Hospital with traumatic injuries and placed on life support but died on Jan. 27.

Fox News Digital’s Chris Eberhart contributed to this report.