A Newnham man has pleaded not guilty to murdering his 77-year-old mother in their home last year.
William John Christopher McFardzean Foran, 53, stands accused of strangling and smothering Margaret Foran last April.
A jury of eight women and four men was sworn in this morning at the Supreme Court in Launceston.
Justice Helen Wood warned them that photographic evidence depicting the alleged crime scene was graphic leading to one juror being excused.
The jury were told they had to decide whether Mr Foran, firstly, committed the alleged murder and whether he was of a sound mind.
Several psychiatrists will be called to give evidence about Mr Foran's mental state.
After he was arrested Mr Foran allegedly said that five days before the incident his ``spiritual'' mother told him to kill his ``biological'' mother.
Earlier today senior constable Donna Stafford from Northern Forensic Services was called to give evidence about photos she took of the alleged crime scene.
The trial is expected to run in to next week.