Convinced that his friend was a police informant, drug dealer Christopher Warren Arthur Frank ordered Troy Bellingham off his property at gunpoint.
Then Frank tripped, accidentally discharging the faulty sawn-off rifle he had pointed at his mate's head.
But instead of calling an ambulance, Frank went into his house to consume drugs with another man despite Mr Bellingham's groans.
Frank told the man he didn't want emergency services at his house, west of Brisbane, because they might discover his drugs.
Emergency services weren't called until Frank hatched a plan as Mr Bellingham lay prone outside his house to put the gun in his dead friend's hand and claim self-defence.
When police arrived at his Lockyer Waters property in March 2020, Frank told them Mr Bellingham had died after threatening him with a gun and it had gone off during a tussle.
Frank, 37, was taken to task by Justice Lincoln Crowley after pleading guilty to a string of charges including manslaughter in Brisbane Supreme Court on Thursday.
"Your conduct displayed callous disregard for Mr Bellingham. You were solely concerned for yourself," he said.
"You attempted to cover up what had happened, you staged the scene, you lied to police and incredibly ...you consumed drugs.
"Instead of having the decency to take responsibility for what you had done, you acted like a coward."
Frank had expressed animosity toward Mr Bellingham before the fateful meeting after being told by a mutual friend that his mate claimed to be a police informant.
"Saying s*** like that will get you a bullet or shot," Frank told his friend after hearing Mr Bellingham's alleged claim.
Frank was so upset about the news that he decided to rip off Mr Bellingham in a $650 drug deal.
After Frank refused to respond to numerous messages, Mr Bellingham demanded answers about the drugs he had paid for when he went to his property.
When Frank finally emerged from his house with the gun, he said: "I should shoot you for being a f***ing informant".
Frank told him to leave, frog marching him to his car with the gun to his head.
The gun had a faulty trigger and discharged when Frank tripped and fell forward.
Justice Crowley said Frank may not have intended to kill his mate but he was entirely to blame for Mr Bellingham's senseless and unnecessary death.
"You took a loaded and cocked gun which you knew was faulty and likely to discharge with minimal pressure, pointing in close proximity of the deceased with your finger on the trigger," he said.
"That series of acts ... caused the death of Mr Bellingham."
An emotional Frank looked on as victim impact statements were read in court.
"The day you killed my dad was the day you destroyed my childhood and my life," Mr Bellingham's daughter said.
"The last time I saw my dad I was angry with him, he told me he loved me but I didn't say it back - he will never know how much I love him."
Mr Bellingham's other daughter chose to read her statement in court.
"My entire life has changed and I don't feel safe any more," she sobbed.
Mr Bellingham's sister spoke of how losing their "Troy Boy" had left a void in their heart ensuring their family would never be whole again.
Frank was sentenced to 12 years in jail.
He will be eligible for parole in September 2028, with 1006 days in custody declared time served.
