The boyfriend of Gabby Petito, whose body was found at a national park in Wyoming after a cross-country trip with him, has been charged with unauthorised use of a debit card.

It comes as searchers continued looking for Brian Laundrie on Thursday in Florida swampland.

A federal grand jury indictment filed in US District Court in Wyoming alleges Mr Laundrie used a Capital One Bank card and someone’s personal identification number to make unauthorised withdrawals or payments worth more than 1,000 dollars (£730) during the period in which the 22-year-old went missing.

It does not say who the card belonged to.

Police are searching for Brian Laundrie
Mr Laundrie is a person of interest in the disappearance of his girlfriend, Gabrielle “Gabby” Petito (Phelan M. Ebenhack/AP)

FBI spokeswoman Courtney Bernal declined to reveal the nature of the payments made on the debit card.

Special Agent in Charge Michael Schneider said an arrest warrant issued on Wednesday over the alleged fraudulent use of the bank card will allow law enforcement across the country to continue pursuing Mr Laundrie while the investigation continues into Miss Petito’s death.

Mr Laundrie has been named a person of interest in the case.

The case has garnered enormous public interest, but also raised uncomfortable questions over the unequal attention given to the hundreds of cases of Native American and other minority women missing or murdered across the United States.

In Florida, searchers on Thursday spent a fifth unsuccessful day looking for Mr Laundrie in the forbidding wilderness preserve near his parents’ home.

The search at the Carlton Reserve park was set to resume on Friday, said Joshua Tayler with the city of North Port, where the park is located.

People donate money and distribute candles that will be later be lit in unison in support of the Petito family in Blue Point Nature Preserve Park in Blue Point
People donate money and distribute candles that will be later be lit in unison in support of the Petito family in Blue Point Nature Preserve Park in Blue Point (Brittainy Newman/AP)

It began after Mr Laundrie told his parents he was going there, several days after returning alone on September 1 from his trip to the west of the US with Miss Petito.

The indictment says the unauthorised use of the debit card occurred from about August 30 to September 1.

Mr Laundrie family lawyer Steven Bertolino said it is his understanding the arrest warrant was related to activities that occurred after the death of Miss Petito, and not to her actual demise.

Miss Petito was reported missing on September 11 by her parents after she did not respond to calls and texts for several days while the couple visited parks in the West.

Her body was discovered on Sunday in the vicinity of a remote, undeveloped campground along the border of Grand Teton National Park in northwestern Wyoming.

Teton County Coroner Brent Blue classified Miss Petito’s death as a homicide – meaning her death was caused by another person – but did not disclose how she was killed pending further autopsy results.