Melbourne's murder-accused Bourke Street driver James 'Dimitrious' Gargasoulas believes he is "the second coming of Christ" and is mentally unfit to stand trial, a psychiatrist says.
The 28-year-old is facing an investigation hearing in the Victorian Supreme Court to determine if he is fit to stand trial over the 2017 rampage that killed six people, including two children.
Consultant psychiatrist Lester Walton on Wednesday said Gargasoulas is schizophrenic and continues to have delusions.
"He has cosmological, Aboriginal and religious beliefs that he is the messiah and it's all mixed up together," he told the jury.
Dr Walton said Gargasoulas believes "he is the second coming of Christ".
One of his letters read by defence barrister Theo Alexander states "to all spiritual people, this is the most important spiritual information as promised by a Jesus in the Holy Bible".
In the same letter Gargasoulas also says "I was born for a reason" which was to "reveal the truth" and "have the scales removed from your eyes".
In another letter the accused refers to himself as "King James George Gargasoulas" and "ruler of the universe".
Dr Walton said the letters are similar to comments Gargasoulas has made about Aboriginal royalty, the illuminati and being the messiah.
"Are these views that you believe he genuinely believes?" Justice Lex Lasry asked.
"Yes, Your Honour," Dr Walton replied.
The psychiatrist also said: "he has said straightforwardly to me that he is the messiah".
Dr Walton told the jury his report on Gargasoulas' mental state ultimately concludes the 28-year-old is not fit for trial.
Gargasoulas faces six counts of murder and 28 charges of attempted murder over the Bourke St mall rampage on January 20, 2017, as well as other charges.
The hearing continues.