A murder trial heard that James Dunleavy, 40, answered "no comment" to most of the questions put to him during an hour-long interview.
He also denied arguing with mother Philomena, 66, from Dublin, who was visiting Dunleavy's flat in Edinburgh.
The High Court in Edinburgh heard that the questions were put by Detective Constable Brian Manchester after Dunleavy was detained on July 8 as he left a shop near his home. A month earlier the dismembered body of Mrs Dunleavy had been unearthed from a shallow grave on Corstorphine Hill, a 15 minute walk from the flat.
Advocate depute Alex Prentice QC, prosecuting, asked the detective: "Throughout your dealings with Mr Dunleavy did he ever exhibit any emotion?" Det Con Manchester told him: "No, not during the interview."
The trial heard that Dunleavy also said he had not seen the photo reconstruction of his mum's face which had been publicised.
Professor Caroline Wilkinson, 48, of Dundee University - an expert in craniofacial identification - said she was called in after police launched Operation Sandpiper to try to identify the mystery woman found on Corstorphine Hill.
She described how, beginning with computerised details of a skull, a picture of a face could be built up and features, such as hair, added.
Lucina Hackman, 44, also of Dundee University, who attended the post mortem, described tell-tale marks which showed a saw had been used on Mrs Dunleavy's thighs.
The trial earlier heard the dismembered body had lain so long in a shallow grave that medics had difficulty working out how she died.
Dunleavy, 40, denies battering his mother to death Philomena, 66, of Marino, Dublin between April 30 and May 7 last year.
He also denies attempting to defeat the ends of justice by trying to cover up the alleged murder and destroy evidence.
The trial continues with the prosecution expected to close its case today.