image source, EPAimage captionBrian Laundrie and Gabby Petito

The FBI has issued a federal arrest warrant for Gabby Petito's boyfriend for his "use of unauthorized devices" following her death.

The indictment says Brian Laundrie used a debit card and PIN number for accounts that did not belong to him between 30 August and 1 September.

Ms Petito's body was found on Sunday inside a park the couple had visited.

Mr Laundrie is currently missing. His family say he was last seen on 14 September.

Officials are searching for him at a Florida nature reserve.

The couple had been travelling for several weeks before 23-year-old Mr Laundrie returned home to Florida alone with their white van on 1 September. He did not contact police or the Petito family on his return.

Ms Petito's family reported her missing 10 days later. On Sunday, the body of the 22-year-old was found in the Grand Teton National Park in Wyoming. The coroner ruled her death a homicide but gave no indication as to how she died.

The indictment issued on Wednesday by the US District Court of Wyoming says Mr Laundrie obtained over $1,000 (£730) with the debit card transactions.

"While this arrest warrant allows law enforcement to arrest Mr Laundrie, the FBI and our partners across the country continue to investigate the facts and circumstances of Ms Petito's homicide," FBI Special Agent in Charge Michael Schneider said in a statement.

Mr Laundrie's lawyer, Steve Bertolino, told Fox News that it was his "understanding that the arrest warrant [was] related to activities occurring after the death of Gabby Petito and not related to her actual demise".

media captionWatch: Police stopped Gabby Petito more than two weeks ago

Mr Laundrie's family reported him missing over the weekend. They claim he left for a hike and never returned. He is considered a "person of interest" in the disappearance but had refused to speak with investigators before disappearing.

The search for Mr Laundrie has focused on a 24,000-acre nature reserve near his home in North Port, Florida. Police are using dogs, drones, and all-terrain vehicles for the search, which officers say is complicated by difficult, swampy terrain.

Earlier this week, investigators also searched the Laundrie family home. Agents were seen removing several boxes from the house and towing away a silver Ford Mustang.

  • EXPLAINER: What do we know about Gabby Petito's boyfriend?

It is still unclear what happened when Ms Petito went missing. Two weeks earlier, on 12 August, police in the southern Utah town of Moab were called to a possible domestic violence incident involving the couple.

Police released bodycam footage which showed Ms Petito crying and complaining about her mental health to officers. She also said the couple had been arguing more frequently.

The officers recommended they spend the night apart but did not file any charges.

Ms Petito last video-called her mother on 24 August to say she was leaving Utah and heading to the Teton mountain range in Wyoming, according to Rick Stafford, the family's lawyer.