SUSPENDED Sydney paramedic Trent Speering fumed that the NSW Ambulance Service was run by "degenerates" and was bigoted towards redheads before shooting dead his elderly mother and himself, a court has been told.

On June 11, 2008, the 40-year-old visited his 70-year-old mother, Monica Speering, at her Baulkham Hills home and shot her twice in the head before covering her with a blanket and resting her head on a pillow.

Mr Speering then killed himself, a coronial inquest into both deaths heard today.

The day after the shootings, Sydney's The Daily Telegraph newspaper opened a letter to the editor from Mr Speering detailing the reasons for his actions.

John Agius, counsel assisting the coroner, outlined some of contents of the letter in the NSW Coroners Court today.

"There are two main reasons as to why I've taken the action I have,'' Mr Agius read from the letter.

"One is that there is a lot of bigotry towards people with red hair in this workplace ... and I've copped my share in my lifetime...

"I work for the Ambulance Service of NSW and you would be hard pressed to find an organisation more morally bankrupt, and run by a bigger bunch of degenerates if you tried.''

Mr Speering went on to say that he would kill his mother and himself.

The letter triggered a police investigation but officers arrived at the house too late.

Mr Agius told coroner Mary Jerram that repeated recommendations from paramedic colleagues and medical experts that Mr Speering undergo a psychological assessment, had not been adopted.

"There are issues here about the duty of care for the ambulance service to Mr Speering as an employee ... given what the ambulance service ought to have known of Mr Speering's mental state,'' he said.

The inquest, set down for two weeks, is due to hear from numerous witnesses, including senior NSW Ambulance management.