"He identified himself as Russell Mendoza and said he had just shot 30 of his neighbour's dogs, which surprised me a little, but when he got down to it he said he had permission but the owner of the dogs was getting uptight and things could get nasty.''
The next day, a friend of Mr Hargreaves laid a complaint with police.
Mendoza also went to see Mr Rose and showed him a note which the court has already been told said there would be no legal "comeback'' from the shooting and was signed by Mr Hargreaves.
Mr Rose said he drove to the property to "get my head around the scene'' and to speak to Mr Hargreaves.
"He was numb, I guess that's the way you could describe it. He was on another planet. He had in his hands a small puppy who had survived and he didn't have a lot to say.''
He said what Mendoza had done "beggared belief''.
Mr Rose said he found dead dogs in a cage. One had been shot in the head at point-blank range with a shotgun.
"I saw a whole pile of puppies who had been shot and thrown on a drip-tray.''
Mr Rose said the drip-tray had bullet holes in it and there was steel machinery around the drip-tray.
"A .22 bullet is dangerous at a mile, those bullets would have gone straight through a puppy ... goodness knows where they could have gone after that.''
He said the bullets would have ricocheted had they hit steel.
"They don't stop until either they run out of oomph or hit something else.''
Mr Rose has yet to be cross-examined.
Earlier, former SPCA investigator Sacha Keltie was asked by Campbell's lawyer Barry Hart if she had been concerned about 21 puppies kept in a van and a further eight puppies in a cage.
She replied: "I did make a note that the dogs appeared in good condition, they were obviously deceased but their post-mortem condition - I didn't have concerns about their condition.''
Mendoza's lawyer Joe Koppens said the evidence called by his client would be that he shot one dog in the head at point-blank range.
He asked her if the dogs were a breed used for dog fighting.
Ms Keltie said she had no experience with dogs used for fighting and could not say.
The trial before a judge alone, continues.