Pawel Rodak, 20, was convicted of a lesser charge of culpable homicide after standing trial by jury for the murder of Heriot-Watt University lecturer Roger Gray.
Mr Gray, 64, was stabbed 114 times after inviting Rodak to his home in Edinburgh for sex. He was found dead from massive blood loss and a deep knife wound in his heart.
The gas cooker in his kitchen had been left turned on and a lit candle left beside it.
During the trial, Professor Anthony Busuttil, 66, former Regius Professor of Forensic Medicine at Edinburgh University, said he had never seen so many stab wounds on a victim in his long career.
Rodak appeared for sentence before temporary judge Michael O’Grady at the High Court in Livingston yesterday. But the judge said the unusual nature of the case made it necessary for him to obtain a risk assessment on Rodak before passing sentence.
Murdo MacLeod QC, who was appointed by the court to represent Rodak after he refused to instruct lawyers, said his client now expressed regret for the killing. “He has asked me to publicly express his regret for this offence and his profound condolences for the family of Mr Gray.”
Mr MacLeod said Rodak now wanted to be treated for the mental health problems which had led him to kill.
He reminded the court that the accused had been diagnosed as suffering from post traumatic stress disorder (PTSD) after being violently raped by a man when he was aged 15. Although he was self-harming while in prison during the trial and suffering from an eating disorder, he was now in much better health.
Mr MacLeod added: “This was his one and only foray into the world of prostitution. Mr Rodak would be extremely unlikely to put himself in such situations again.”
He suggested that the accused’s PTSD could be treated in prison. However, Judge O’Grady said: “This is a very unique case and there are quite extraordinary features.
“The current information on managing risk is non-existent.
“Given that it is such an unusual situation and given the dreadful nature of this offence it appears to me that the closest and most professional inquiry would be necessary, regardless of what at the end the outcome would be.
“I say that naturally in relation to the public interest and it would appear also to be in the interest of Mr Rodak.”
He stressed he had formed no final view on sentence.
The judge appointed Rajan Darjee, consultant forensic psychiatrist at the Royal Edinburgh Hospital, to prepare a psychiatric report on Rodak to establish whether he poses a risk to public safety if he is eventually released.
Rodak was remanded in custody until the psychiatric report is prepared. He will be sentenced at the High Court in Edinburgh on September 21.