A 67-year-old farmer who shot dead a father of three, sparking a missing persons search that lasted weeks has been sentenced to life in prison.

John Gerard Benny Della Franca earlier this year pleaded guilty to killing 40-year-old Tony Ditri on August 27, 2021 in WA's South West.

The discovery of Mr Ditri's empty vehicle on the outskirts of Pemberton, 300 kilometres south of Perth, sparked a large-scale search which lasted weeks before his remains were found on September 15.

Concerns over avocado theft

Della Franca called police to his Pemberton farm on August 22, 2021 — five days before Mr Ditri's murder — over concerns of sheep, cattle and avocadoes being stolen, the Supreme Court in Busselton on Friday heard. 

He gave officers a list of people he believed could be responsible, with Mr Ditri among those named.

The court heard Della Franca told police if he caught a trespasser on his property, he would put a chain on their car and drag it into the bush, "never to be seen again".

At about 4pm on August 27, Della Franca's security camera system picked up movement at the Pemberton rubbish tip, which was located near his property.

Prosecutor Brett Tooker said Mr Ditri, who owned a local gardening and landscaping business, was at the rubbish tip emptying lawn clippings when he was confronted by Della Franca.

Using a shotgun, Della Franca then shot Mr Ditri twice, once in the chest and arm, and then again in the back.

Della Franca buried Mr Ditri's body at a nearby farm, disposing of an apple crate and fertiliser bag he used to transport the body at another location.

Mr Tooker said Della Franca put marron nets in Mr Ditri's truck to make it appear as though the man had "gone missing in a fishing misadventure".

Later that night a friend went to the tip to look for Mr Ditri, who had three young children, again setting off movement on Della Franca's CCTV camera.

Mr Tooker said the man left the site after Della Franca began firing gunshots through the trees.

Della Franca was arrested on August 28 and charged with Mr Ditri's murder four days after he was last seen.

Community traumatised

Mr Tooker said the Pemberton community had been hit hard by Mr Ditri's death.

"His loss caused enormous trauma and heartache to this tight knit community," he said.

"He was completely innocent. He was unarmed and incredibly vulnerable, while Mr Della Franca had a loaded, 12-gauge shotgun.

The court heard Della Franca told police he'd only shot Mr Ditri once, and his death had been an accident.

Defence lawyer Paul Yovich said it had taken Della Franca a long time to admit what he'd done.

He described Della Franca as a "man with good qualities" who was unlikely to reoffend in the future.

Della Franca was sentenced to life in prison with a minimum parole period of 20 years.

He showed no reaction as the sentence was handed down.