Three deaf people were caught on CCTV using sign language to plot the murder of their housemate moments before he fell to his death from a balcony, a court has heard.
Robert Wright, who was also deaf, died from catastrophic head injuries after falling from the balcony of the second-floor apartment in Melbourne's east on January 15 last year.
Georgia Fields, Jake Fairest and Warwick Toohey are accused of murdering the 36-year-old, they were each found unfit to stand trial due to their intellectual disabilities and are subject to a special hearing, the Daily Mail reports.
In footage from the foyer and lift of the apartment building which was analysed by an Auslan interpreter, the trio allegedly discuss the best way to kill Mr Wright.
"Ms Fields asked Mr Fairest 'you want dead or alive and how die?" Prosecutor Christopher Dane QC told the Victorian Supreme Court.
"Mr Fairest ... signs 'can strangle neck area, what do you think?'
"Mr Toohey signs to Mr Fairest 'strangle risky' and Ms Fields signs 'fall good, fall good'", the prosecutor told the court.
Fields and Fairest have pleaded not guilty while Toohey has pleaded not guilty on the grounds of mental impairment.
Toohey and Fairest are intellectually disabled while Fields suffers from atypical autism and has low intelligence.
"The prosecution case is Mr Wright was pushed in a plan between his housemate and his two other friends," Dane told the court.
"Fairest and Toohey, the Crown says, lifted him up and forced his body over the railing of the balcony while Fields looked on."
A neighbour who was smoking a cigarette outside will give evidence he saw Wright holding onto the balcony ledge while an unknown person held his wrist, said the prosecutor.
That person then let go of the 36-year-old.
Defence counsel for Toohey said his client is mentally impaired and not legally responsible for his actions.
"Much of what the Crown says happened, we do not disagree with," barrister Theo Alexander said in his defence reply.
"The issue in relation to Toohey is how his mental capacity interacts with his legal liability."
Alexander said Toohey was unable to form an intention of murder and was unable to appreciate what was happening.
Defence counsel for Fairest said his client was not involved in Mr Wright's murder.
'He says 'I wasn't part of an agreement and I wasn't involved in the ultimate act of pushing him off the balcony',' said barrister David Gibson.
Peter Kilduff, representing Fields, said his client denied murdering Wright.
"She told police ... 'Warwick and Jake both picked Robert up and pushed him off the balcony'," he said.
The prosecution says five days after Wright died, Fields told a friend on Facebook messenger that she, Fairest and Toohey "pushed Robbie over the balcony".
"She stated she didn't want to tell the truth to police as she wanted to be free and not in jail," Dane said.
In a special hearing it is open to the jury to find the accused has committed the offence, or find the accused is not guilty, or not guilty by reason of mental impairment.
The special hearing before Justice Jane Dixon will continue on Wednesday.