But RDA manager Wendy Sellars told the Chronicle on Monday that no one was prosecuted because police said there wasn't enough evidence.
A police spokesperson confirmed this saying officers had made several inquiries into the incident, including talking to the person who uploaded the footage on to social media.
"It was established they did not know the offender and CCTV footage from the premises did not show the offender either.
"Police have exhausted all current investigation options and have advised the victims of this," the police spokesperson said.
Mrs Sellars said it was unfortunate the people got away with it, even with the video that was posted on social media.
"It would have been good if they had done some work here and seen the damage they had caused."
She said the horses had recovered after a long holiday and will be reassessed for training within the next week.
Police encourage anyone who may have information about this incident to contact Whanganui police on 06 349 0600 or give information anonymously via Crimestoppers on 08000 555 111.