American Humane Association officials have severed ties with an employee who confessed to "playing down" the near death of a tiger on the set of Ang Lee's acclaimed Life Of Pi.

Gina Johnson's email to a colleague about the incident was obtained by The Hollywood Reporter as part of an investigation into animal exploitation and loss of life on film sets.

The publication's editors posted the expose, headlined Animals Were Harmed, online on Monday (25Nov13) - just ahead of the weekly magazine's street release - and 24 hours later, an Aha spokesman told CNN that Johnson no longer worked for the watchdog organisation.

Johnson had been employed as an on-set monitor, given the task of making sure filmmakers and trainers observed strict rules about animal welfare and care on the set of the 2012 film.

In the April, 2011 email she sent to a colleague, Johnson stated a Bengal tiger named King "damn near drowned" during a scene.

She wrote, "The worst thing was that last week we almost f**king killed King in the water tank. This one take with him went really bad and he got lost trying to swim to the side. Damn near drowned."

She added, "I think this goes without saying but Don't Mention It To Anyone, Especially The Office. I have down-played the f**k out of it."

Aha officials have yet to respond to requests for information about the circumstances surrounding Johnson's departure, but in a statement released on Monday, they insisted The Hollywood Reporter's investigation "distorts" their work.

In the article, Aha critics claim the statistics the organisation's bosses quote to support their successes are inflated by the inclusion of high volumes of insects.

Meanwhile, a spokesman for movie studio Fox has denied Johnson's claims the Life of Pi tiger almost drowned, stating, "The tiger, King, was never harmed and did not 'nearly drown' during the production. We take on-set safety very seriously and take every precaution necessary to ensure that no one - animal or human - is harmed during the production of our films."