An Alberta man who admitted to punching and stomping his father to death and attacking his sister on the Trans-Canada Highway after a night of heavy drinking has been sentenced to 3½ years in prison.

Tristan Wesley, a 29-year-old Morley resident, was sentenced Thursday after pleading guilty to manslaughter in the July 2015 killing of Myles McLean.

The Morley resident, who had originally been charged with second-degree murder, also pleaded guilty to assault causing bodily harm in relation to the attack on his sister.

The court heard that the accused and his 55-year-old father had been drinking at a casino and were being driven home by the sister when the men got into an argument and Wesley started hitting his dad.

The vehicle stopped and McLean was beaten during two separate instances on the roadside — the second time when he tried to stop Wesley from striking his sibling after she tried to intervene.

Crown sought up to 7 years

The Crown had sought a prison term of five to seven years, while the defence argued for either a suspended sentence with probation, or a jail term of up to two years.

According to an agreed statement of facts, Wesley had been at the Stoney Nakoda Casino when he was cut off from purchasing drinks.

He had his sister stop near a rest area, where the two men got out and a fight ensued. Wesley knocked McLean to the ground and began to beat him before his sister tried to break it up.

Wesley then focused his aggression on his sibling; punching her, threatening her and dragging her onto the road.

McLean got back on his feet and stopped that attack but Wesley overpowered his father once again. McLean told his daughter to save herself before he was knocked unconscious. The daughter then drove to a nearby overpass to call 911.

Officers arriving at the scene discovered a lifeless McLean with a pulverized jaw and a bloodied Wesley nearby.

An autopsy determined McLean died from blunt-force trauma and suffered multiple skull fractures. A toxicology report found Wesley had a substantially high blood-alcohol level at the time of the fight.

Wesley's sentence includes credit for time served and he will remain behind bars for two years followed by 18 months of probation.