One of the men accused of murdering a North Otago farm worker has described the mindsets of the men allegedly involved.

Steven Boskell, Robert Cummings and brothers Ryan and Jacob Geary-Smart are on trial in the High Court at Dunedin for the murder of Justin McFarlane.

Boskell told the court how another defendant told him 'he saw his brain.'

He then talked about how the group stopped at a location and the attack sank in.

"Jake's sitting next to me going, 'take me home, please take me home, I wanna go home',"

"Ryan was sitting in the front seat talking about killing himself.

"What was Mr Cummings doing?

"He was sitting next to me rolling a joint."