Brian Laundrie: Police are searching for boyfriend of missing influencer Gabby Petito

The family of a US man whose fiancée disappeared during a road trip say he is now missing too.

Brian Laundrie, 23, is a person of interest in the case but police say he is not wanted for any crime.

He and Gabrielle “Gabby” Petito, 22, set out on a cross-country campervan trip in July, documenting their adventures on social media.

But on 1 September, Mr Laundrie returned home alone. Ms Petito’s family later reported her missing.

This week local police said they had been trying to speak to Mr Laundrie but he was refusing to talk.

In a statement on Friday, police said Mr Laundrie’s family told them they had not seen their son since Tuesday. In a statement, police said they were “frustrated” by the developments.

“For six days, the North Port Police Department and the FBI have been pleading with the family to contact investigators regarding Brian’s fiancée Gabby Petito. Friday is the first time they have spoken with investigators in detail,” it read.

“We are not currently working a crime investigation,” it added. “We are now working a multiple missing person investigations.”

Mr Laundrie’s sister Cassandra told ABC News she had mostly been learning what has been happening from the news.

“Obviously, me and my family want Gabby to be found safe. She is like a sister and my children love her, and all I want is for her to come home safe and sound and this be just a big misunderstanding,” she said.

A lawyer for Ms Petito’s family said: “All of Gabby’s family want the world to know that Brian is not missing, he is hiding. Gabby is missing.”

The couple set off on a nomadic nationwide road trip in a white Ford Transit van in July, posting updates on social media.