Brian Laundrie may have died of drug overdose, says expert who reveals how investigators will confirm cause of death

BRIAN Laundrie may have died of a drug overdose, an expert has claimed, as she reveals how investigators will confirm his cause of death after an "inconclusive" autopsy.

The 23-year-old man was cited as the only "person of interest" in the homicide of his fiancée, Gabby Petito, and his skeletal remains were discovered weeks after he went missing.

According to authorities, the bones are being sent to an anthropologist "for further evaluation" as his family eagerly await results.

It could take weeks for them to get an answer as forensic anthropologists conduct DNA tests and look for any signs of weapon evidence to help determine how a person died.

Dr. Erin Kimmerle, a forensic anthropologist based in South Florida, told The Sun exclusively: "I think it's very possible they will find a cause of death if there were injuries or some type of trauma that affected the skeleton.

"If there is soft tissue available for toxicology that could be insightful in cases of drug overdose.

"But most likely the scene, evidence at the scene, and the skeletal injuries themselves will help lead to the cause of death."

Dr Kimmerle also believes Laundrie took his own life in Carlton Reserve in Florida, and thinks police have a strong case for a murder-suicide conclusion due to domestic violence and four other factors.

"There seems to be an overwhelming amount of evidence linking the two cases, including a history of domestic violence," she said.

"Add to that witnesses who place them together, the well documented timeline, GPS data from their cars, and cell phone records.

"It seems there is a strong circumstantial case for a murder-suicide."

Read our Brian Laundrie live blog for the very latest news and updates...

Florida cops didn't know Brian Laundrie was missing until four days after he vanished - despite his family's lawyer insisting he contacted the FBI immediately.

The timeline of Laundrie's disappearance was thrust back into the spotlight after his remains were discovered a month after Gabby was found strangled to death in Wyoming following their road trip.

Attorney Steve Bertolino was asked to clarify the timeline after questions were reignited by speculation over how and when Laundrie died.

He was reported missing to the Northport Police Department by his parents Chris and Roberta on September 17.

It later emerged that the couple last saw their son on September 13, when they said he set out for a solo hiking trip.

In interviews this week, Bertolino revealed for the first time that he'd contacted the FBI to alert them that Laundrie was missing when he didn't return home on the 13th.