Noelene June Jordan and Cedric Harper Jordan have pleaded not guilty to murdering Shane Barker, 36, at his home in Campbell Town in Tasmania on August 2, 2009.
The pair were charged in May 2020 following an extensive police investigation.
During opening submissions in the trial on Friday, Crown prosecutor Daryl Coates said the couple's daughter Rachel had been in a "toxic" relationship with Mr Barker.
Mr Coates said Rachel was unhappy about a proposed financial settlement with Mr Barker and there were tensions over the custody of their daughter.
"They hated Mr Barker and wanted him out of (Rachel's) life," Mr Coates told the Supreme Court of Tasmania in Launceston.
He said the couple left their house in Swansea, some 69km from Campbell Town, at 6pm with a .22-calibre rifle and drove to Mr Barker's home.
Mr Coates said Mr Barker went to shut the gate on his property when he was shot three times in the back and once when he was laying on the ground.
Mr Coates said it was the Crown's case the Jordans had "had enough" and formed an agreement to kill Mr Barker.
"(They) went to Mr Barker's house where they shot him and left him to die," he said.
It was highly likely Cedric Jordan pulled the trigger because he was an experienced shooter who owned guns and ammunition, Mr Coates said.
Lawyers defending the Jordans will make their opening submissions on Wednesday in the trial which is expected to last several months.
Mr Coates said there would be evidence of Cedric Jordan saying "we should get rid of the bastard" in relation to Mr Barker prior to the alleged murder.
He also allegedly told a man on a camping trip, "don't worry about him, I've got a bullet with his name on it".
The court was told Rachel left Mr Barker for a previous boyfriend in 2007.
Mr Coates said Cedric Jordan showed a rifle to Rachel and her new partner in late 2008 or early 2009 and said "this could be a good rifle to get rid of someone with".
The rifle used in the alleged murder has never been found, Mr Coates said.
He told the court identical bullet cases to one found at the crime scene were discovered at a Jordan family property in the Central Highlands.
During investigations in 2016, he said, a crane was used to move a shipping container at the Central Highlands property and the cases were found underneath.
Mr Coates said the Jordans changed their story about their whereabouts on the night of Mr Barker's death during initial police interviews.
The police investigation was taken over in 2015 by a unit with detectives who specialised in complex cases.
On the night he died, Mr Barker had earlier had dinner with his parents before returning home with an empty biscuit tin and some ironed shirts.
Mr Barker's body was found by police in the hallway of his home.
Mr Coates said a lack of disturbance to the property pointed to a premeditated killing by somebody who knew where he lived.
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