A BALLOCH man who battered a stranger to death after finding him in bed with his mother has been jailed for four years and eight months.

Sean Mahan, 21, discovered Dumbarton man Stewart McKellar, 33, and his mum Lavina ,50, together whilst his father was working offshore.

Mahan attacked Mr McKellar at his family home in Balloch before lashing out at Lavina.

After the brutal assault, Mahan called a friend and said: "This guy was sleeping with my mum. I think I've killed him."

Mahan, of Luss Road pleaded guilty to the August 2014 culpable homicide of Mr McKellar at the High Court in Glasgow in December last year.

Sentence had been deferred to the High Court in Edinburgh in order for the court to obtain reports about Mahan's character.

On Wednesday, judge Lord Turnbull told Mahan that the assault on Mr McKellar was a 'gross over reaction' to what he had witnessed.

He added: "You engaged in a sustained violent attack in which you repeatedly punched a man who did nothing but try to protect himself.

"You have left the victim's family in a state of grief and despair and there is nothing that I can do that will alleviate these circumstances.

"This was a sustained and uncalled for act of violence."

At the previous hearing, the court heard how Mr McKellar died after being out with friends at the night club in the Lomond Park Hotel in Balloch on August 23.

He met Lavina at the club and after talking to each other, they headed back to her home where they started kissing.

She invited Mr McKellar upstairs as she was 'worried someone would come in'.

But the court heard her son then suddenly returned home in the early hours and found his mum in bed with Mr McKellar.

He barged the door open and yelled: "What are you doing? How could you do this to my dad."

His father John Mahan was working offshore at the time.

The court heard there was then a 'prolonged assault' lasting up to 20 minutes on Mr McKellar which involved repeated punching.

Mahan then turned on his mum slapping her on the head and calling her 'a slut'.

As a badly beaten Mr McKellar lay naked on the floor, Mrs Mahan managed to run away.

Mahan then called a friend and said: "Mate, you will need to come down. This guy was sleeping with my mum and I think I have killed him."

Paramedics soon arrived at the house after being alerted to what had gone and discovered a hysterical Mrs Mahan.

Prosecution lawyer Douglas Fairlie QC told the court: "There were clear signs of a disturbance - broken furniture and glass as well as items of male and female clothing on the bedroom floor."

Attempts were made to save Mr McKellar but he was pronounced dead.

Mahan was later found by police at a friend's house hiding in a kitchen cupboard.

He asked about Mr McKellar and claimed: "I only punched him. What would you have done?

"My dad's working offshore and I come home to find my mum in bed with someone else."

On Wednesday, defence solicitor advocate Murray Macara QC told the court that his client was full of remorse for what happened.

As Mr Macara spoke, Mahan sat in the dock, shaking and sobbing.

Mr Macara said Mahan was now suffering from panic attacks and anxiety.

He added: "There was a degree of impulsive behaviour on his part. He formed the view that his mother had betrayed his father.

"This caused him to act in the way in which he did.

"Upon release from prison he hopes to join his father in the Aberdeen area as he doesn't see a future for himself in the Balloch area."

Lord Turnbull also imposed a 16 month sentence on Mahan for assaulting his mother. However, that sentence will run concurrently with the four year eight month imposed for culpable homicide.

Mahan was then taken to the cells of the high court to begin his sentence behind bars.