His personal doctor, Conrad Murray, was later convicted of involuntary manslaughter because of the drugs found in Jackson's body.
"The thing that was odd that I found myself periodically looking at was his head, his scalp," Detective Scott Smith, from the Los Angeles Police Department (LAPD), says in the documentary.
"Because whenever he was out in public he was wearing a wig.
"Looking at his scalp, the top of his head had been severely scarred.
"Hardly any hair at all on the sides. To what he had looked like in public with the flowing hair, that was a bit different."
In 1984, Jackson suffered second-degree burns when his hair caught fire while filming an ad for Pepsi.
As a result, he suffered hair loss and then became addicted to prescription painkillers.
"I'm not defending his use of prescription medicine by any means, but when you experience something like that it kind of opens up the door for painkillers and whatever else that may lead to," the detective added.
Detective Dan Myers, also of the LAPD, said Jackson was "relatively healthy".
The detectives also described the chaotic state of Jackson's bedroom, where he was found.
A child's doll was found on his deathbed and needles were strewn all over the floors. A noticeboard with ads feature young children was also in the room, along with a number of bizarre post-it notes.
