The family of a Perth man who died after being stabbed through the heart have said they are “devastated” his killer’s mum has escaped jail for attempting to pervert the course of justice.

Robbie Smullen (23) was convicted last month of killing 22-year-old Barry Dixon.

A jury at the High Court in Edinburgh rejected his defence of self-defence and returned a majority verdict of culpable homicide.

Sentencing Smullen on Friday, judge Lady Carmichael said the killer had been “disinhibited by alcohol and the effects of sexual jealously”.

The judge added that no sentence imposed could “repair or lessen the harm done to the family of Barry Dixon”.

Lady Carmichael sentenced Smullen to nine years and three months imprisonment.

Smullen’s mother Mary Smullen (46) had been on trial alongside him, accused of pretending to police that Barry was stabbed by Shannon Beattie. During the trial she changed her plea to guilty to attempting to pervert the course of justice.

Lady Carmichael ordered Mary Smullen to carry out 180 hours of unpaid work. The judge said Smullen’s “false information” did not lead cops on the wrong trail for “very long” but did lead to Ms Beattie being initially treated as a suspect.

Barry’s aunt Jade Taylor said Mary Smullen should have been sent to prison for her crime.

Jade said not sending her to jail “set a dangerous precedent’’.

She added: “Days on, we are still in utter disbelief and we are hoping for news that the Crown Office will appeal this unduly lenient sentence.

“In many ways for us, the suffering inflicted on Barry by this woman while he lay bleeding and dying was far more depraved than her son Robbie Smullen’s actions when he stabbed Barry.

“It is in my mind constantly that when Barry saw his killer’s mum enter the property, an older woman, a mother, he would have assumed they were going to help him and the thought of him realising they were not there to help him live is very hard to live with.”

Barry was knifed in the chest after going back to the flat with Smullen’s “on/off” partner Shannon Beattie (25).

Robbie Smullen, who was convicted after an eight-day trial, gave his mother a thumbs-up as she left the dock and he was led to the cells downstairs.