Jolee Callan was shot and killed while on a hike in an Alabama state park: Facebook

A series of photos posted to a murderer's Instagram account appear to reveal the events of her final hours before she was killed by her ex-boyfriend and pushed off a cliff.

Jolee Callan, 18, was shot twice in the head by former partner Loren Bunner after he convinced her to go hiking in east Alabama in August 2015.

A series of photos posted on Bunner’s Instagram account show Ms Callan’s final hours with her ex-boyfriend. The first picture shows her sitting in a car with a dog on her lap, with the caption: “On our way to go hiking <3”.

Three more photos show Ms Callan walking the dog and later holding the dog while looking out at a view after hiking up a mountain in Cheaha State Park. The final photograph shows her taking a picture of another view.

The pair had reportedly split up months earlier but had agreed to go on the hike together as friends. Ms Callen reportedly sent a message to a friend the night before, joking: “If something happens to me, you’ll know who I was with,” The Mirror reports.

Bunner shot Ms Callan on the trail before pushing her off the cliff and leaving her body.

Police said Bunner called 911 to report he had “murdered his ex-girlfriend” while driving home from the crime scene and pulled over to wait for the authorities, according to the Shelby County Reporter.

Kiba's dragging @joleeisakitten on a mission. A post shared by Loren Bunner (@lorendaniel) on Aug 30, 2015 at 7:51am PDT

He had shot Ms Callan in the back of her head and between the eyes, according to Alabama.com. Authorities seized a Bear Claw .22 firearm from Bunner when they reached him and found blood on his steering wheel. Police also reported “a large amount of blood” at the scene where Ms Callan was shot.

Bunner, now aged 22, pleaded guilty to the murder last month, claiming that he and Ms Callan had created a suicide pact together but that after shooting her, he was unable to go through with shooting himself.

He had originally been granted youthful offender status, meaning he could only be sentenced to a maximum of three years for the crime. This was later overturned and Bunner was tried as an adult, receiving a 52 year prison sentence in July this year.