A tragic incident unfolded earlier this year in the Arizona desert when a hot air balloon crashed, claiming the lives of four individuals.

Reports indicate that the pilot, Cornelius van der Walt, had elevated levels of ketamine in his system, as revealed by a medical examiner's report obtained by USA Today.

According to the report, van der Walt had a concerning amount of ketamine in his blood, enough to impair his ability to operate a vehicle. It was noted that he did not have a prescription for the drug, and rescue teams attempting to resuscitate him did not administer ketamine.

Van der Walt, a 37-year-old resident of Eloy originally from South Africa, was navigating the balloon with 13 adults on board on January 14. Following the departure of eight skydivers, the balloon encountered difficulties, leading to a tragic outcome for van der Walt and four other passengers.

WATCH: RFK JR. EXPLAINING HIS VP PICK NICOLE SHANAHAN

The National Transportation Safety Board (NTSB) released a preliminary report on January 25, indicating that the balloon crashed in a desert area southeast of Phoenix due to an unspecified issue. The NTSB report highlighted observations from mobile phone videos showing the balloon descending with a deflated envelope, accompanied by sightings of the burner flame.

WATCH: 11 STATES ARE NOW SUING THE BIDEN ADMIN

Investigations revealed thermal damage near the envelope's mouth, frayed sewn rim tape material, and multiple damaged panels. The crash resulted in the fatalities of van der Walt, Chayton Wiescholek, Kaitlynn Bartrom, and Atahan Kiliccote, with Valerie Stutterheima surviving with critical injuries.

As the NTSB continues its investigation, the final report on the crash is anticipated to be concluded within a year.