Tipsters have reported a dozen Brian Laundrie sightings in North Carolina over the last week, according to officials

• A dozen sightings of Brian Laundrie have been reported in North Carolina since Thursday.
• The Haywood County Sheriff's Office in the western part of the state said authorities have investigated each one.
• Laundrie is wanted on charges of using an unauthorized debit card and spending around $1,000.

Authorities in North Carolina have investigated at least a dozen reported sightings of Brian Laundrie, the missing Florida man wanted by the FBI on charges that he used an unauthorized debit card and a person of interest in the case of his deceased fiancé, Gabby Petito.

The Haywood County Sheriff's Office, located in the western part of the state near the border of Tennessee, released a statement Monday confirming that the office has been inundated with "a number of calls" reporting sightings of Laundrie over the past several days.

Authorities have "thoroughly" investigated each tip, according to the sheriff's office, but none have materialized in anything concrete.

A spokeswoman for the office told NBC News that tipsters have reported 12 sightings of the 23-year-old since Thursday.

One of these calls was placed by a man around 2:30 a.m. on Saturday claiming he was almost certain he had spoken to Laundrie.

"He was talking wild. He said that his girlfriend left him and he had to go out to California to see her," the man told the 911 dispatcher, according to NBC. "He was acting funny. And I wasn't sure what he looked like. And then … I went and parked and pulled up the photographs of him. And I'm 99.99% sure that was him."

The same caller also told authorities the man he spoke to was driving a white pickup truck. The driver of the truck signaled to the man that he wanted to speak to him in a parking lot near the Appalachian Trail, he said.

"I'm telling you - it was him," the caller told dispatch.

A spokesperson from the Haywood County Sheriff's Office did not immediately respond to Insider's request for comment.

Laundrie was last seen by his family on September 13, when his parents say he left their home in Florida for a hike in Sarasota County's large Carlton Reserve, carrying only a backpack. Laundrie's parents initially told authorities they had last seen him on September 14, but changed their story via their lawyer earlier this week.

His parents reported him missing on September 17 - days after Petito's mother reported her daughter missing on September 11 after Laundrie returned from a cross-country road trip without her on September 1.

On September 19, a body that authorities believed was "consistent with the description" of Petito was found in Grand Teton National Park. The FBI and the Petito family's lawyer later confirmed that the remains belonged to Petito, and her death was ruled a homicide shortly after.

Laundrie is wanted for questioning in relation to a grand jury indictment revolving around his activities following Petito's death, the FBI announced last month. On September 22, a Wyoming court issued a federal arrest warrant for Laundrie, alleging that the person of interest in Petito's case defrauded and used an unauthorized debit card.

Police across the country have debunked several reported sightings of Laundrie since his disappearance, including alleged sightings in Alabama and Florida.