A Vancouver Island animal refuge has boosted its security after an intruder brutally killed 20 rabbits last month.

Susan Vickery of the Ears Sanctuary in Coombs, B.C. said she found the rabbits stomped or crushed to death at the compound on June 14.

"I arrived at the front gate in the morning and found one of my rabbits dead and obviously crushed," Vickery told ctvbc.ca. "I went across the barn and it was just tragic. It was tragic to see these little bodies just smashed down."

The feral rabbits were among hundreds transported from the University of Victoria campus to animal sanctuaries in B.C., Texas and Washington last year after UVic announced plans for a mass extermination to control the population.

Vickery initially thought an animal might have entered the sanctuary, but found evidence of a human intruder on the facility's fencing. She now believes the slaughter was the work of a single individual.

"I don't think it was drunk teenagers or somebody who was high. It was very deliberate. There was no falling down or bumping into things, there was no breakage," she said.

Vickery said she waited to go public with the killings because she did not want to draw attention to the sanctuary before she could upgrade security.

Donors have now provided the Eears Sanctuary with an alarm system and surveillance cameras, and a full-time volunteer will be watching the facility at night.

Still, Vickery says the possibility of another break-in has cost her much sleep over the past weeks.

"You have the fear, that looming fear that something else is going to happen," she said. "These animals have become like pets for me. So yeah, it's been hard."

She has alerted the Ministry of Environment and Mounties about the break-in, but says she cannot imagine who could be responsible.

Last September, dozens of rabbits from the sanctuary were killed after escaping from the property.

The bunnies were shot by neighbours who complained about the animals trespassing and eating their grass.