A devastated father spoke of his heartbreak over losing his 7-year-old daughter after her mom shot and killed his other daughter and her two daughters from a new relationship in what the police determined to be a murder-suicide.

Olivia Blackmer, 7, passed away after undergoing a brain surgery and spending five days at the hospital following the shooting that took place in the family home in Wyoming.

Olivia’s three sisters, Brailey, 9, Brooke, nearly 3, and Jordan, 2, died at the scene while she fought for her life, but sadly, didn’t make it.

In a crowdfunder post, Olivia’s family wrote that she “fought so, so hard up til the last minute.”

“Olivia is with her sisters now,” the family wrote.

“Her body and her brain had been through too much, medication helped but we reached a point where medical options were exhausted and her body only continued to get worse.”

On the day of the tragedy, the girls’ mother, Tranyelle Harshman, 32, called the police and alerted them of the shooting in the family home, according to the Big Horn County Sheriff’s Office.

In a release, the force said that Harshman told them what happened to her daughters and said she was going to do the same to her, revealing the location of the each of the girls within the house.

Once at the scene, Harshman was still responsive, but died a day later, February 11, at a hospital.

According to her husband, Cliff, Harshman wasn’t “a monster,” but she suffered from mental health issues, including PTSD and postpartum depression. Conditions she was receiving treatment for.

Olivia and Brailey’s father, Quinn Blackmer, expressed his sorrow over the devastating loss of his two daughters whose mom shot.

“The amount of devastation we feel and are going through is so much,” he wrote, saying he finds ‘peace’ in “knowing that my babies don’t have to be apart from each other and they can also be with their other sisters.”