A major breakthrough has occurred in the case of Brian Laundrie, who disappeared from his house in Florida in early September.

The investigation into Brian, whose fiancée Gabby Petito was found dead in Wyoming last month, has uncovered new details about his earlier movements, as well as traces of human activity in a nature reserve that has been the key area of the search.

Police found the remnants of a campsite that appeared to be used recently in Florida’s Carlton Reserve, a sprawling 24,565-acre wilderness near Laundrie’s family home that has been closed to visitors, a source close to the family told CNN on Wednesday.

Chris Laundrie, Brian’s father, joined law enforcement and went to the reserve to help them look on Thursday morning.

“Chris was asked to point out any favorite trails or spots that Brian may have used in the preserve. Although Chris and Roberta Laundrie provided this information verbally 3 weeks ago it is now thought that on-site assistance may be better,” the family’s attorney Steven Bertolino said.

The North Port Police Department also confirmed that a notice was placed on a seemingly abandoned vehicle that belonged to the Laundrie family close to the reserve on September 14th.

Brian originally told his family that he was heading to reserve the last time they saw him.

The ongoing search for Brian comes as law enforcement try to piece together the events that led to the death of 22-year-old Gabby Petito.

Gabby and Brian had been travelling across the United States in a ‘van life’ trip that they were documenting on social media.

Gabby was officially reported missing on September 11th: 10 days after Brian returned home from Florida without her.

In the days following, Gabby’s body was found in a national park in Wyoming, and the coroner determined she died by homicide.

Brian originally refused to speak with police when questioned, and then went missing himself.

Brian is now the subject of a federal warrant as a key person of interest in Gabby’s case, as well as for unauthorised use of another person’s debit card.

He was last seen on September 13th by his family, and has been missing for 25 days.

Image credits: Facebook / Instagram @gabspetito

This article first appeared on Over60.