Items believed to belong to Brian Laundrie, whose girlfriend, Gabby Petito, was found dead after he returned home alone from their cross-country road trip, were discovered Wednesday in a Florida wilderness park, according to the FBI and a Laundrie family attorney.

Laundrie’s parents, Chris and Roberta Laundrie, took part in the search Wednesday with the FBI and police from North Port, Florida, more than a month after Laundrie was reported missing after heading to the vast Carlton Reserve park.

“After a brief search off a trail that Brian frequented some articles belonging to Brian were found,” attorney Steven Bertolino said in a text to the Associated Press. “As of now law enforcement is conducting a more thorough investigation of that area.”

Quoting a senior law enforcement source, NBC News reported that human remains had also been found near the items, but had not been identified.

The items believed to belong to Laundrie were found in the Myakkahatchee Creek environmental park on Wednesday as the search continued for clues in the killing of Petito.

The Sarasota county medical examiner’s office confirmed that officials had been summoned to the reserve after the items were found.

Laundrie, 23, is a person of interest in the killing of Petito, who was reported missing on 11 September by her parents while the couple was on a cross-country trip out west.

The case generated 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. Petito is white.

Laundrie had been missing since 14 September, two weeks after he returned home alone from the cross-country trip. His parents said he left their house in North Port with a backpack, but left behind his wallet and cellphone.

Laundrie’s disappearance prompted days of searching in the swampy Carlton Reserve wilderness park by scores of FBI agents and law-enforcement teams using drones, sniffer dogs and underwater equipment.

In late September, Laundrie was charged in his absence with the unauthorized use of a debit card.

He was indicted by a federal grand jury for allegedly using a Capital One Bank card and someone’s personal identification number to make unauthorized withdrawals or charges worth more than $1,000 while Petito was missing.