Investigators in South Carolina have revealed that a mother used a gun she stole from her parents to shoot dead her two children, a woman she believed to be her estranged husband's new girlfriend and then herself as part of an elaborate revenge plot.

Pickens County Chief Deputy Creed Hashe said 36-year-old Jessica Edens called her estranged husband twice on July 13 - once around the time she killed her son and daughter, and again before committing suicide.

Hashe said the same .40-caliber handgun used to kill 28-year-old Meredith Rahme in a parking garage below downtown Greenville apartments was used to kill 9-year-old Hayden King and 5-year-old Harper Edens.

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Scorned wife: Jessica Edens, 36, (left) shot 28-year-old her estranged husband's suspected new girlfriend, Meredith Leigh Rahme (right), on July 13 as part of a revenge plot

Edens then used the same gun, which she had stolen from her parents, to shoot in the head her nine-year-old son from a past relationship, Hayden, and five-year-old daughter Harper (pictured)

Hashe said in a news release Monday that text messages show Jessica Edens making plans to 'create everlasting consequences' for her estranged husband, Benjamin Edens, after a Family Court hearing over the custody of their daughter, which left her feeling 'distraught.'

The investigation has confirmed that Jessica Edens drove her black Jeep SUV directly from the parking garage in Greenville just moments after Rahme was murdered near the Greenville-Pickens Speedway, where it was later discovered by a passing motorist.

FULL STATEMENT FROM SHERIFF CLARK: 'As we struggle to understand how a parent could possibly come to a decision such as this, we have to focus on tomorrow and the opportunity to provide services and solutions to those that feel that their life and the lives of their loved ones must end in order to find peace. We live in a stressful world during difficult times but there are resources that stand ready to offer help and assist you if you feel that you have no other options left in life. Please reach out to law enforcement so that we can be the bridge to lead you to a road of recovery. In time, you will see that all things come to pass and you too can become a stronger person with hope and faith in a brighter future. All of us need a helping hand from time to time as we walk through life and asking for help is not a sign of weakness that any of us should be ashamed of.' Advertisement

Based on a phone call made by Mrs Edens to her husband while he was in the presence of Greenville authorities, along with other evidence, it is believed siblings Hayden and Harper were shot by their mother while seated in the rear cargo area of the SUV. There were no signs of a struggle.

Detectives believe the mother killed her children before she made what would be her final phone call to her husband, and then she turned the gun on herself as she sat in the backseat of the Jeep with their bodies.

As previously reported, first responders found the Jeep locked and with the engine still running at around 5pm on July 13.

Deputies used a baton to break the driver’s side window in order to get inside. There, they found Edens, her son and daughter all dead.

Autopsies performed on the deceased the following day determined that each person had a single gunshot wound to the head.

A statement from Sheriff Rick Clark read, in part: 'As we struggle to understand how a parent could possibly come to a decision such as this, we have to focus on tomorrow and the opportunity to provide services and solutions to those that feel that their life and the lives of their loved ones must end in order to find peace.'

The shooter is believed to have accused Rahme (pictured) of being a 'homewrecker' in an anonymous online post the day before the murders

Harper (left) and Hayden (right) each died of a single gunshot wound to the head. Police found no signs of struggle in the back of their mother's SUV

DailyMail.com reported earlier this month that Rahme was the target of an anonymous online attack posted on July 12 and since deleted.

'This little girl has no self respect and no morals. She dates married men who have children and she doesn’t even want or like kids,' the vicious post attacking Rahme read.

'Her character speaks enough for her. Remember homewrecker, that karma is a b---h, just like you. You will get what you deserve,' the screed went on, posted to a website that ostensibly identifies 'homewreckers'.

Two hours after Rahme was shot, deputies found the suspect SUV locked and running with Edens and her two children inside, each dead from a single shot to the head seven miles away in Easley, Pickens County Chief Deputy Creed Hashe said.

Hashe called it a 'graphic and horrific' scene. The .40-caliber handgun was found inside the SUV.

Rahme had called police twice less than three weeks ago to ask how she could deal with harassing text messages, phone calls and online postings from Edens, Thomas said.

Police approached this SUV which was locked and still running near Greenville, South Carolina

Officers smashed the driver's side window of the car to gain access to the vehcile

Police said Edens and her two children had fatal gunshot wounds to their heads when they discovered the three inside Edens' locked SUV with the engine running

Edens' estranged husband had called Easley police on July 12 to ask them to check on their daughter shortly after he received a disturbing text message from Edens and the two had been in court to discuss custody of the 5-year-old girl, authorities said.

The officer who went to the home found the family planning to eat popcorn and watch a movie. One of the children was speaking to the husband, according to the police report.

The officer asked Edens if there was any chance she could get back with her husband and she said instead she was going to expose his yearlong affair in court, the police report said.

Rahme worked with Edens' husband, Thomas said. He refused to give any other details about their relationship.

Thomas said authorities had no indication Edens was planning violence before the shooting.

'There is some indication that about the time of the custody decision that she had some sense of inflicting violence either on the children or on herself or both. But that wasn't discovered until after she was discovered last night,' Thomas said.

Rahme was found dead in the driver's seat of her car, authorities said.

Thomas said the tragedy of the shooting touched several families.

'It is important to remember there are fathers who have lost children to this senseless violence and our heart goes out to them,' Thomas said.