The jury in the Antonie Dixon trial at the High Court in Auckland has retired for the night and will resume deliberations on Friday.
Mr Dixon, 40, is charged with murdering James Te Aute in Auckland and seriously injuring two women with a samurai sword near Thames in 2003.
The jury retired shortly before 3pm on Thursday, after Justice Williams took almost four hours to sum up complex legal arguments in the case.
Much of his time was spent telling the jury how to consider the issue of insanity.
The defence says Mr Dixon was insane at the time - although it also says he shot Mr Te Aute in self-defence.
The Crown says the accused carried out the crimes in a cool and intentional manner, that he knew what he was doing, and he was not insane.
The jury has five other charges to consider relating to the same day. They include kidnapping, illegally using a firearm, and breaking and entering.