Thieves have shot and skinned a North American bison on a rural property in New South Wales, prompting the offer of a reward of $20,000 from its owners who are eager to catch the killers.

Key points: The bison, named Chief, was shot and skinned around 10pm on June 15 at Central Bucca, north of Coffs Harbour

The bison, named Chief, was shot and skinned around 10pm on June 15 at Central Bucca, north of Coffs Harbour At eight-feet tall and weighing at least one-and-a-half tonnes, owner John Van Stroe says he was a "gentle giant"

At eight-feet tall and weighing at least one-and-a-half tonnes, owner John Van Stroe says he was a "gentle giant" Police believe people in hunting groups may know who is responsible, and pictures may have been posted online in closed groups

John Van Stroe keeps a small herd of bison on his property at Bucca, on the NSW Mid North Coast and 'Chief' was their patriarch.

"Chief stood about eight feet tall — he had a huge presence," Mr Van Stroe said.

"The gentlest giant you have ever come across — you would go out to the paddock and call him and he'd come running up, you could hand feed him."

Cruel and unusual

Chief was shot at the Bucca property at around 10pm on June 15, but the family did not notice the incident.

Mr Van Stroe's sons heard gunshots at the time, but assumed it was neighbours shooting foxes.

It wasn't until the following day they realised something was wrong.

"A lady came up the driveway and said, 'One of your bison doesn't look too well near the fence' so I went down there and poor old Chief had been shot and skinned for his fur," Mr Van Stroe said.

"We were devastated, absolutely devastated.

"I didn't know what to say, what to do — I didn't call the police until the afternoon."

Chief the "gentle giant" was treated as a pet by the Van Stroe family. ( Supplied: John Van Stroe )

'Cowardly act'

Police said the killing was a "cowardly act" and NSW Rural Crime Coordinator Detective Inspector Cameron Whiteside believed it was likely people in the hunting community knew who was responsible.

Detective Inspector Cameron Whiteside said the killing was a cowardly act. ( ABC News )

"Typically, people that kill these animals for trophies will skite about it to mates or even post it on social media in a closed group," he said.

Police are also concerned for the safety of people living nearby as it is believed Chief was shot with a high-powered firearm.

"It's an area that has residential properties, it puts the neighbouring properties and people around there in danger because the projectiles can travel some distance and you just don't know what's behind what you're shooting," he said.

Detective Inspector Whiteside said those responsible were likely to face a number of charges.

"We strongly believe there'll be firearms offences, cruelty to animals charges and also an offence which comes under the umbrella of stealing cattle or killing cattle, which would hold up to 14 years in jail, so it is quite a serious offence and it is very, very disturbing."

Big money for bison

Bison are worth big money, and Mr Van Stroe estimated Chief's value at $20,000.

Apart from their meat, bison hides attract premium prices.

"I have just been to America and bought a bison coat over from there and that was $12,000," Mr Van Stroe said.

Chief was shot in the spine, which led Mr Van Stroe to believe the culprits knew what they were doing.

"That's how you take bison down, that way you don't damage the hide if you are to skin them," he said.

However, the sheer size of Chief meant the killers could only take half the hide.

"You can see that they tried to skin him from his legs up, but they couldn't turn him over — he weighs at least one-and-a-half tonnes," Mr Van Stroe said.

"Usually trophy hunters will take the head as well, but they didn't do that.

"They did take the best part round his neck which has his mane on it which is very attractive, but very cruel."