A father and his teenage son accused of executing a 38-year-old homeless man will plead guilty or not guilty to the charges against them in three months’ time.

South Australian Police have charged Keith Yandle, 46, and his son Marco, 19, with the joint murder of father-of-two Steven Murphy after his remains were found buried on a remote property north of Adelaide in April.

A tip-off led the cops to the Kudla property, about 47km north of Adelaide, where they found a marijuana farm and a gravesite within a man-made bunker.

Prosecutors allege Keith executed Mr Murphy with an unlicensed firearm at close range on the night of February 19.

They allege Marco and his father Keith equipped themselves with a bat and an illegal firearm after they suspected an intruder was on the property.

The duo allegedly went out to check on their shed at the family property in Kudla when the intruder, Steven Murphy, was shot.

The teen, who had been carrying a baseball bat, allegedly shone a torch over Mr Murphy as his father shot the man three times.

The prosecution alleges the entire incident was caught on the family’s CCTV system, but hard drives containing the footage were hidden in the roof of the home, along with the gun.

Keith and Marco were arrested and charged on April 16 and both men have been denied bail.

Marco asked the Adelaide Magistrates Court to release him on home detention bail – a request that was immediately dismissed due to the severity of the charges.

He then applied for that decision to be reviewed in the Supreme Court, arguing his age, lack of criminal history and previous good character should be reason enough for the dismissal to be overturned.

Marco was the vice-captain of Trinity College, a private co-ed school in Gawler that charges up to $7,060 a year for senior school students.

Justice McDonald, however, ruled in May that a murder charge was the most serious offence and meant the teen was not automatically entitled to bail.

“It is an offence committed in a vast range of circumstances, by people from many different walks of life.”

“It is not uncommon for a person charged with murder to have been of previous good character appearing in court for the first time.

“In my view, this is a very serious allegation of murder and I dismiss the application.”

Marco had no visible reaction to the decision, but outside court his mother left weeping.

Adelaide Magistrates Court heard on Tuesday the prosecution had concentrated the charges against Keith to include only the cultivation of a controlled plant, possession of a firearm without a license and possession of ammunition with a license in addition to the murder charge.

An earlier charge against Keith of cultivating a commercial quantity of a controlled plant was dropped.

Keith and Marco, who are both on remand and appeared in court via videolink, will now enter their pleas to the charges on January 16.