Accused killer Christopher David Navin attended the funeral and wake of the man he is alleged to have murdered.
Friends have told his ACT Supreme Court murder trial that they spoke to Navin at Nicholas Sofer-Schreiber's memorial in January 2014.
They then saw him at music gigs in the weeks after, where he exhibited strange behaviour.
Navin, 29, has pleaded not guilty by way of mental impairment to the murder of Mr Sofer-Schreiber in his Lyneham home on Boxing Day 2013.
The Crown alleges Navin's motive to kill his estranged friend had been anger and revenge.
But the defence claims their client had been suffering a psychotic illness at the time.
The court has previously heard that Mr Sofer-Schrieber suffered 73 stab wounds, with three to the neck causing death.
The Crown alleges the former housemates had fallen out over a repair bill and Navin sought revenge after Mr Sofer-Schrieber ignored his attempts to mend the friendship.
The court heard on Tuesday from a number of friends of both men, with one describing Navin as socially awkward and prone to saying and doing "weird things".
One friend reported Navin had stared at him awkwardly at a pub in the weeks after the funeral.
When asked what was wrong, the witness told the court that Navin shook his head and said his mind had been somewhere else.
Navin also asked the man if he had enjoyed his visit to Canberra, which the witness considered odd as he had rushed back to Canberra from overseas on the news of his close friend's death.
Another friend told the court on Tuesday that Navin had been a "bit fidgety" and did not socialise well at a concert at The Phoenix Pub soon after the funeral.
The man said Navin's behaviour had deteriorated to the point he could not hold a conversation when he next saw him at a gig at The Basement.
The witness, who had flatted with the victim and Navin, reported the two men clashed in their time as housemates and Mr Sofer-Schreiber would yell at the accused.
He said Navin would not raise his voice and "shrugged off" the arguments.
Earlier in the day, the court heard evidence of the police search of the northern NSW property where Navin drove to on the night of the murder.
Jurors were shown aerial photos of the property, near Grafton, which depicted where two knives – which the Crown alleges are the murder weapons – were found by police divers in a dam.
The trial continues on Wednesday.
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