The two teenagers accused of killing Ihaia Gillman-Harris went to a party just hours after they bashed him in an Auckland motel room.
A witness told the High Court Leonard Nattrass-Berquist and Beauen Wallace-Loretz were acting normally that night, but their demeanour changed the next morning when they learned Mr Gillman-Harris had died.
Nattrass-Berquist broke down as he told the court about talking to his mother about what had happened that night.
The defence lawyer asked what he was upset about, to which Nattrass-Berquist said it was remembering "everything".
"It's stressful being [in the stand]," he said.
The two teens claim Mr Gillman-Harris tried to assault them, and they acted in self-defence, but the Crown says it was a planned robbery.