Dr. Ingrid N. Visser, an orca expert and founder of the Orca Research Trust, continues to ponder the origin of a wound suffered on the lower mandible of Nakai, one of the “killer whales” that form the backbone of SeaWorld San Diego’s menagerie.

As reported on the blog of Outside magazine correspondent Tim Zimmerman, Visser traveled to San Diego to attempt to observe Nakai shortly after news of his injury broke. While here, she captured perhaps the most graphic photo of Nakai’s wound that has been made publicly available.

“Regardless of the source of the wound, I didn’t buy the story from SeaWorld that Nakai had ‘come into contact with the pool,’ as to me such wording implied a light brush past, or perhaps at worst a bump into the side of the tank. Clearly such a striking wound wasn’t from a light brush or even a ‘bump,’” writes Visser.

Based on the available photos at the time (also included in the previous link), Visser said she believed the injury could have been caused by a sharp edge, such as are found at the gates between the different holding pens where the orcas are kept between shows, and between those pens and the main performance tank.

Her initial assumption was bolstered by UC Davis Wildlife Center veterinarian Nancy Anderson, who disagreed with theories that the injury was the result of an attack by another whale.

“The edges of that wound are so smooth. If it were the teeth of an orca, there is no way it could look like that,” Anderson is reported to have said. “It looks more consistent with the animal getting snagged on something and pulling away from it.”

Visser, however, “had heard that there were rumors around that SeaWorld was using laser treatment – and such treatment could be used to debride (‘clean up dead tissue’) from the edge of a wound.” From this, she theorized “that such treatment may have impacted on the visual nature of the edge of the wound,” and set off for SeaWorld herself.

On arrival, Visser claims to have been obstructed in her investigation by SeaWorld staff.

“When I was in the park the trainers and security guards were not happy with me trying to photograph Nakai and had me stop photographing from certain points,” writes Visser. “They obscured other observation points by moving sun umbrellas and outdoor gas heaters in front of viewing spots and they moved Nakai to prevent me taking photos at all. The security guards would not let me talk to the trainers either.”

Visser’s photo that has been circulating on the internet captured several clear puncture marks separate from the main wound, lending credence to the theory that Nakai was hurt as a result of an attack by other orcas performing that night.

SeaWorld has released no further statements beyond saying that Nakai is receiving treatment for the injury and is interacting normally with the other orcas in its San Diego collection.