Internet sleuths have claimed that the Brian Laundrie and Gabby Petito cases are more complicated than the authorities have revealed. 

Investigators think drugs were involved when it was discovered that they were selling goods on Depop with the phrase "too high" written on it. 

Gabby's Depop account has sweaters and caps with the phrase "too high" written on them. 

pink tie-dye cropped graphic sweatshirtwith the overlaying silver and pink text "using cricket and heat press" was pinned on the account "thingsgabbydoes,"  with the location posted in Miami, United States.

Gabby said she "hand-dyed" the sweater herself. 

Meanwhile, the bucket hat with flowery designs and a silver and pink "too high" embroidered on it is said to be customizable and available in a variety of sizes. 

The exact number of persons who bought the product is unknown. 

Cause of Death for Brian Laundrie 

Dr. Erin Kimmerle, a forensic anthropologist, told The Sun last week that Brian Laundrie may have died from a heroin overdose. 

"If there was soft tissue available for testing, that may be informative in situations of a drug overdose," she said in the interview.

Brian's autopsy revealed that the cause of death was "inconclusive." 

Other internet sleuths noticed that Brian Laundrie's social media pages were decorated with drug-related items like photographs of LSD tabs with "Adventure Time" characters, among other things. 

Social media users also questioned Brian Laundrie and Gabby Petito's drug usage on a sub-Reddit, where a forensic psychologist stated that drugs may have had a role in the latter's death. 

It would depend on how much and how often they used narcotics, according to a forensic psychologist.

Another Reddit user wondered if Brian's return to Florida to refill a drug prescription was the reason he left Gabby alone in Utah from Aug. 17 to Aug. 23. 

However, Brian went home because he wanted to empty out their shared storage locker and left their stuff at his parents' house to save money, according to the Laundrie family lawyer Steven Bertolino. 

READ ALSO: Brian Laundrie Update: THIS May Be Fugitive's Horrible Cause of Death, According to Twitter and the Police

Brian Laundrie Substance Abuse?

"He could be highly motivated to go home for an Adderall prescription," the forensic psychologist speculates, "since it's a regulated substance that isn't easily transferred."

Brian Laundrie may have been addicted to Adderall, according to the expert, which heightened his drive to come home and get his prescription filled. 

But it would be difficult for Brian to know the exact answers if drugs played a major role in this case without knowing his history of mental health and psychiatric medications, including side effects, compliance, and responses to the medications, as well as his school records and social functioning.

READ MORE: Brian Laundrie's Parents Secret Exposed: Chris and Roberta Told Police Where to Find Son In Exchange For Immunity?