Ewen Macdonald received police diversion for poaching on private land in Taihape with Callum Boe in 2006.
Documents unsealed by the High Court at Wellington also show slain Feilding farmer Scott Guy once told his sister, Nikki, that Macdonald was "the worst thing that happened to our family" and the farm would be better off without him.
The fresh revelations have emerged after Fairfax Media was granted access to the court file on Macdonald, who was acquitted last month of murdering his brother-in-law, Mr Guy.
They come after Justice Simon France lifted suppression on three further charges admitted by Macdonald when he was arrested for murder in April last year.
The jury at Macdonald's trial did not hear how he and Boe used a hammer to kill 19 calves belonging to Foxton farmer Paul Barber in August 2007.
They also emptied a milk vat on the neighbouring farm of Nigel Sexton and his father Graham Sexton that same day, and then burned down a 120-year-old duck shooting whare belonging to the Sextons in March 2008.
Macdonald still faces sentencing for those crimes along with three others that were revealed in court.
Boe has already been jailed for his part.
In committal statements, viewed yesterday, Macdonald's father Kerry Macdonald said his son and Boe also got caught after they choppered into public land near Taihape in 2006 and walked on to the Wipaki family farm where they shot a Sika deer.
Kerry Macdonald said he learned about the incident after someone asked him if Ewen had been to court yet, prompting him to ask his son.
The committal documents - which are witness statements used by the prosecution to justify putting a person on trial - also featured evidence from Mr Barber and the Sextons that show Macdonald was poaching on their property.
Mr Barber told police he found a deer carcass on his land in 2007 with its head and back legs removed.
In June that year, he and a friend went out at night to hunt and found a white utility on his land with a letter addressed to Scott Guy on the front seat.
Mr Barber called police after learning from Mr Guy's father, Bryan Guy, that Macdonald had the utility at that time.
About six weeks later, Mr Barber was told by a farm worker that something was wrong with some of his calves.
"I got to the shed and I could tell that about 18-20 calves were dead, killed by a sharp blow to the head."
"I was sickened by what I saw."
About the same time, neighbouring farmers Nigel Sexton and his father Graham Sexton also found animal carcasses and unknown human tracks on their Foxton farm.
They pointed the finger at Macdonald, who originally denied it, but then said it was "just that easy" and their property was not the only one he had been poaching on.
Kerry Macdonald said he confronted his son about the poaching and said. "you've got to f...ing admit what you've done."
The motivation behind Macdonald and Boe's crimes was revealed in September when Boe appeared in Queenstown District Court and was sentenced to two years' jail for his offending.
The details of that appearance were suppressed until this week.
In sentencing notes obtained by The Dominion Post, Judge Kevin Phillips said Boe's explanation for the crimes against Mr Barber and the Sextons was retribution for being trespassed from the area.
Boe was spoken to shortly after the murder because he had worked on the Feilding farm co-managed by Macdonald and Mr Guy.
He admitted illegally hunting on the Barber and Sexton properties between 100 and 200 times but denied any involvement in the crimes against Mr Guy.
The High Court committal documents also included a brief of evidence from Nikki Guy.
In it, she recounted a conversation with Scott Guy at a concert in 2008 when he told her how he disliked Macdonald and thought the farm would be better off if he wasn't there, the court documents reportedly show.
"He said that Ewen was the worst thing that happened to our family."
Justice France noted Mr Guy was "intoxicated and probably affected by drugs" at the time, according to the report.
- Fairfax Media
Is this the best summer ever?Related story: Wellington sizzles in January heat