Disturbing text message Brian Laundrie sent days after killing Gabby Petito revealed

Killer Brian Laundrie sent a series of haunting text messages to a friend just days after murdering his fiancée Gabby Petito on a road trip.

Days after the devastating murder of Gabby Petito - which is the new subject of Netflix's American Murder docuseries - the killer sent multiple messages to a friend, describing the 'fun' they had on their travel adventures.

He failed to include that he had strangled his partner to death, sometime around 28 August, 2021, but later admitted to the crime in a suicide note.

Gabby, aged just 22, went missing in August 2021 while travelling across the US in a campervan with Brian. After failing to hear from her for weeks - and despite Brian quietly arriving at his family home in Florida and refusing to speak with authorities - her family launched a missing person's campaign on 11 September.

Gabby's body was discovered 19 September, 2021, and an autopsy determined that she'd died via 'blunt-force injuries to the head and neck, with manual strangulation' three to four weeks prior.

Days after Gabby's body being found, Brian fled, triggering a nationwide manhunt by police. But in a devastating twist, Brian was found dead a month later in the Myakkahatchee Creek Environmental Park in Florida.

An autopsy determined that he died as a result of a self-inflicted gunshot wound to the head.

Gabby Petito and Brian Laundrie set off on a US road trip before he would take her life (Instagram/@gabspetito1)

A note found next to his body read: "I ended her life. I thought it was merciful, that it is what she wanted, but I see now all the mistakes I made. I panicked. I was in shock."

"From the moment I decided, took away her pain, I knew I couldn’t go on without her," he added.

But prior to this, Laundrie had sent a string of nonchalant and disturbing messages to a friend, describing the couple's trip.

"Trip was good," he wrote to his friend Ben on 4 September.

He also said: "Gab and I had fun. Tired now, gonna sleep for a week."

The murderer noted that the two had made a 'lot of content' for their joint YouTube channel, and that the trip was a 'once in a lifetime'.

Gabby and Brian were confronted by police shortly before he killed her (Utah Police)

Shortly before Gabby's death, police had intervened as the couple were pulled over for speeding in Utah.

Officers found Petito covered in blood and crying, as it appeared the couple had a fight.

They separated the pair for one night, but failed to take any further action to prevent her murder.

Gabby’s family later sued Brian's parents - Chris and Robert Laundrie - alleging that they knew all along that their son had killed their daughter, but chose not to say anything during the investigation.