Dad speaks out after last surviving daughter dies following mother's murder-suicide of all her kids

The father of the seven-year-old girl, who was shot in the head in a murder-suicide by her mother, has spoken out following his daughter's death.

Olivia Blackmer died on Saturday afternoon (February 15) five days after being taken to hospital following a gunshot wound to the head from her mother, Tranyelle Harshman.

After calling 911, Harshman, 32, shot Olivia and her sisters before she died of her injuries in hospital after turning the gun on herself.

Olivia's sister, Brailey, 9, and two-year-old stepsisters, Brooke and Jordan, all died on February 10 at the scene of the crime in Wyoming.

Olivia survived and was taken to a local hospital before being airlifted to another facility for treatment, however, her death was confirmed by her father, Quinn Blackmer, who has since taken to Facebook to share a heartbreaking statement after losing his young daughter (via PEOPLE).

Olivia Blackmer died in hospital (Facebook/Katelynn Blackmer)

He wrote: "The amount of devastation we feel and are going through is so much. Please give all families involved our time and space during this extremely difficult time in our life.

"Funeral arrangements and updates to what we think the world needs to know will be on my Facebook but will also be on the GoFundMe.

"Speaking of that, from the bottom of our hearts we want to thank every single person that has donated and prayed and fasted for us and our family and our beautiful Olivia.

"Your kindness and generosity has been so much and we just ask that you continue to pray and keep us all in your thoughts.

"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."

The dad had previously told KTVQ that he was 'furious' with Harshman, adding (via PEOPLE): "I’m trying my hardest to bury that for a while and to focus on the now, because that anger isn’t going to bring my child back."

Olivia's stepmom Katelynn Blackmer also shared the devastating news through a GoFundMe page setup to pay for Olivia's medical expenses, as well as for the kids' funeral arrangements.

Olivia and Brailey's father, Quinn Blackmer, has spoken out (Facebook/Quinn Blackmer)

"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! 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 wrote.

"She kept fighting through it all though until her heart stopped. We are 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. We want to thank each and every one of you for your prayers and support for our family.

"We are in a rough spot with the tragic passing of both daughters. We took time as a family to grieve and be in the moment before letting the world know but wanted to let you all know as we are thankful for all that you have done."

If you have experienced a bereavement and would like to speak with someone in confidence, contact The Compassionate Friends on (877) 969-0010.

If you or someone you know is struggling or in crisis, help is available through Mental Health America. Call or text 988 or chat 988lifeline.org. You can also reach Crisis Text Line by texting MHA to 741741.

You can also call 1-800-985-5990 or text “TalkWithUs” to 66746 at the SAMHSA Disaster Distress Helpline.