Nicolau Francisco Soares, 29, of Western Australia, was found not guilty by reason of insanity to bludgeoning to death Dr Delys Weston and Professor Gavin Mooney at their home in the state's South in December 2012.

Justice David Porter yesterday ordered that Mr Soares must stay detained in a secure mental health facility in the state until a court removes the order.

Justice Porter told the court that Mr Soares believed he had been recruited by the SAS and his mother's attempt to get him medical help would compromise his position.

``It seems that attempts by his mother and Mr Mooney to obtain medication for him in Tasmania triggered their deaths,'' he said.

Defence lawyer Rochelle  Mainwaring told the court the support of his family members was important for Mr Soares's rehabilitation.

But Justice Porter said the issue of public safety ``greatly outweighs the significant restrictions which will follow from the order recommended''. 

Three members of Mr Soares's family prepared letters to the court to emphasise their ongoing support.

Justice Porter said he agreed with two mental health reports that recommended Mr Soares stay in a secure mental health facility in Tasmania with a high level of supervision and restriction, under the Criminal Justice (Mental Impairment) Act.

Justice Porter described the death of the two leading health academics as ``tragic''.

``Tragic too, is that the defendant suffers from such an insidious illness to such a significant extent,'' he said.

``Effectively, by that disease, much of his true self has been lost to his family, and to him.

``That true self seems to be an intelligent, gifted and caring one.''