Local sources said the man used a stick to kill the rabbit and then buried it in the back garden.
But after the matter was reported by a neighbour, gardai dug up the rabbit as part of its investigation into cruelty.
The incident, on May 26, was also believed to have been reported to HSE social workers because the rabbit was killed in front of children.
“The rabbit is said to have bitten one of the children at the house, and the owner killed it with a stick because he felt he couldn’t trust the animal,” a neighbour said.
“But one neighbour who saw what was going on reported it to the gardai in Blanchardstown and the place was turned into a crime scene all of a sudden.
“The forensic guys came and dug up the rabbit and seized the stick it was supposed to have been killed with.
“I heard the dead animal was photographed and taken away for a post mortem.
“The HSE are said to be involved as well, because the children were there when the rabbit was killed,” he added. “It’s the talk of Castleknock.”
The residents of the house where the rabbit was killed declined to comment on the incident.
Gardai confirmed they are investigating an incident of animal cruelty at the address, but would not comment further.
The Dublin Society for the Prevention of Cruelty to Animals (DSPCA) said rabbits need to be handled carefully or they can scratch or bite.
“We are always horrified to hear of violence against pets, especially when that happens in front of children,” said DSPCA spokeswoman Gillian Bird.
“It is illegal to deliberately kill or maim an animal in a way that causes suffering.
“Animals that are to undergo a post mortem are usually brought to the vets’ laboratory in UCD, but it can take a week to 10 days to get results back,” she explained.
The DSPCA said it does not recommend rabbits as pets for very small children because they can revert to a feral state if not handled properly.
“If anyone does have a rabbit and finds they cannot home it properly, we are here to give free advice,” Ms Bird said.