The mother of a Perth murder victim's son was also murdered when the boy was just six-years-old.
Dad Ian Menzies, 55, was found dead within the property on Scott Street at around 8.50pm on Monday, June 7.
Cops, who are treating the death as murder, are said to be following a positive line of enquiry.
A close family friend has told the Daily Record that cops are trying to trace Ian's son Craig Nixon, 36, who has not been seen since his death.
And we can reveal that Craig's mother was also murdered when he was just six.
A source told the Record: "Craig's mum was murdered when he was six.
"They are looking for Craig, he hasn't been seen since his dad was killed.
"I can't believe this has happened."
It's believed Craig was staying with Ian before he was killed.
It is understood that Ian appeared to have sustained head injuries and the focus of the inquiry has centred on a known individual from a nearby psychiatric hospital.
Police are seeking to trace the man, who was known to Mr Menzies, and who had been a resident patient at the city's Murray Royal psychiatric hospital.
It is understood the man who is being sought in connection with the incident had previously been detained in the secure facility at Carstairs Hospital before being moved to Murray Royal.
In a tribute released through Police Scotland, Ian's family said: “Ian was the best dad, grandad and brother in the world.
"He was caring, respected and loved dearly by friends and family. Words cannot express how sorely he will be missed.
"As you can understand, this is a traumatic time for us as a family.
"Although we appreciate your messages of support we would like to respectfully request our privacy at this highly sensitive time.”
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