Police sources said the woman was waiting in the garden for officers to arrive who discovered her husband and son grappling with the intruder when they entered the £1.5million detached cottage on the outskirts of St Ives.
The well-placed source said: 'Police received a call around 4am on Sunday and when officers arrived, found the wife waiting for them in the garden.
'The father was on top of the intruder when police went in and his son behind him with his arm around his neck.
'There had obviously been a struggle and the son was trying to restrain him while his dad tied his hands up.
'They said he was very strong and insisted on staying where they were till police cuffed the burglar.
'At that point they got up and moved away and that’s when officers noticed the man was making strange movements.
'On closer examination they saw he was unconscious and didn’t appear to be breathing. They tried to revive him but were unsuccessful.'
The source added: 'A judicial investigation is now underway. It is up to the CPS to decide what to make a formal accusation against the family but I will say that they have been co-operative at all times and are very shocked and upset at what happened.
'It is obvious to me that if this man’s death is connected in any way to anything the father and son did, that what happened was an accident and not something they intended.
'Police are yet to be officially told how this man died and we do not have the autopsy results at this stage.'Sound a bit odd to you?
Wondering why the family haven’t all been routinely arrested and questioned, perhaps for days, putting a permanent record on file and perhaps jeopardising future holidays or jobs working with children?
Well, it didn’t happen in the UK. That’s why.