Absolutely nothing is known about Bayo, other than he got a job as a coroner in Los Angeles. He has shown members of the BAU the bodies of victims whenever they investigate cases in Los Angeles.
Bayo shows Rossi, Hotch, and Detective Bailey the body of Linda Dean, a woman murdered by a serial killer who is drowning his victims in methanol. He reiterates the victims' causes of death and clarifies that they were not submerged completely in the methanol. He then informs Rossi that the unsub crudely cut out small square samples of flesh from the first two victims' soles, but that Linda Dean's flesh was cut out more cleanly. When Hotch asks if there was methanol found in the wounds on the soles, Bayo replies that there were only trace amounts, indicating that the skin was removed after the victims died. Bayo then informs the agents and detective that there was chloroform found in the victims' blood, and that burning associated with chloroform was only found inside their nostrils. From this, Hotch deduces that the unsub aerosolized the chloroform, turning it into a mist, and Bayo confirms that it could be effective.
A Badge and a Gun
Bayo briefly reappears in the episode, showing Reid the body of Patricia Brannon, the fourth victim of spree killer Andrew Meeks. He clarifies her cause of death and agrees to Reid's assumption that she attempted to chew through the bedsheet that was asphyxiating her. When Reid asks if she was sexually assaulted, Bayo denies it and adds that the previous two victims were also not raped.
- Bayo is the seventh of only nine characters in a medical profession to appear more than once in the show's history. The others are:
- Season Two
- Season Six
- Season Seven
- Season Eight
- Season Nine