Image source, Instagram/ Gabby PetitoImage caption, Gabby Petito (left) was found dead in Wyoming

The fiancé of murdered US blogger Gabby Petito, Brian Laundrie, took his own life, his family's lawyer has said in a statement.

Mr Laundrie returned from a road trip without his fiancée and her body was later found in Wyoming.

Mr Laundrie's body was identified last month using dental records. He had been the subject of a manhunt for more than a month before his body was found.

Police had described him as a person of interest in Gabby Petito's death.

"Chris and Roberta Laundrie have been informed that the cause of death was a gunshot wound… and the manner of death was suicide," the family's lawyer said.

"Chris and Roberta are still mourning the loss of their son and are hopeful that these findings bring closure to both families," Steven Bertolino told ABC Action News.

The case of Ms Petito, 22, and Mr Laundrie, 23, sparked nationwide media attention.

The couple had been documenting their summer road trip in a van through national parks on social media.

Ms Petito's parents reported her missing on 11 September after they had been unable to contact her for a fortnight. Her body was eventually discovered in Wyoming, where the couple had been travelling, on 19 September. A coroner later found that she had been strangled.

It eventually emerged that Mr Laundrie had returned to Florida without Ms Petito on 1 September. Her family repeatedly appealed for her fiancé and his family to co-operate with investigators, but he then went missing himself.

His parents told police they last saw him on 13 September – when he went hiking alone and never returned.

His body was discovered in a Florida park on 20 October.