The only girl who made it out alive after her mom shot her and her 3 sisters in murder-suicide had been fighting for her life. But now, heartbreak deepens.

Police in Wyoming believe Tranyelle Harshman shot her four daughters in the head, killing three of them, before calling 911 and then shooting herself around 1:30 p.m. on Monday, Feb. 10, PEOPLE previously reported.

Tranyelle’s husband Cliff Harshman told KTVQ that he’d lost his 2-year-old daughters, Brooke and Jordan, in the shooting.

Tranyelle’s 9-year-old daughter, Brailey, whom she shares with Quinn Blackmer, also died, while their 7-year-old daughter Olivia survived.

Quinn has since confirmed Olivia sadly died on Saturday, Feb. 15 at 3:44 p.m. local time, per a Facebook post shared on Sunday.

Olivia’s stepmom, Katelynn Blackmer, also confirmed the sad news in an update on a GoFundMe page set up to help the family financially amid the tragedy.

“Olivia is with her sisters now. She gained her angel wings yesterday at 3:44pm. She fought so so hard up til the last minute!” the update read.

“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. She kept fighting through it all though until her heart stopped,” Katelynn, who also shares a 1-year-old son with Quinn, posted, adding that the family is “grateful she hung on as long as she did so we could get some valuable time with our sweet baby girl the last five days.”

Quinn added on Facebook, “The amount of [devastation] we feel and are going through is so much.”

“The peace I find is knowing that my babies don’t have to be apart from each other and they can also be with their other sisters,” he shared alongside a photo of the sisters with angel wings.

Tranyelle’s husband Cliff previously told KTVQ of the shooting, “I know this was something beyond what I can comprehend. I’m a mess. … I don’t even know how to explain this to you. I’m so angry with her for the decision that was made.”

He said his wife had struggled with mental health problems, including postpartum depression and post-traumatic stress disorder.

“People don’t understand how mental illness isn’t just a willpower thing. It’s chemical imbalances in your brain. It’s damaged pathways in your brain,” Cliff added, per the outlet. “She was an incredible mom and she loved those kids.”

“My wife was not a monster,” he told the Cowboy State Daily in a phone interview, stating that his wife was under treatment.

Tranyelle had called 911 on Feb. 10 to report a shooting in the home and told a dispatcher she believed her children were dead, per a Big Horn County Sheriff’s Office release. She added that two of them would be found upstairs in their cribs and the other two would be located in a downstairs bedroom.

Tranyelle also let the dispatcher know that she “could be found in her upstairs bedroom and that she was going to do the same to herself,” per the sheriff’s release.

GoFundMe pages set up to help the Blackmer family and Cliff Harshman had both raised over $100,000 as of Monday, Feb. 17.