Former policemen Roger Rogerson and Glen McNamara made an agreement to go "fishing" early on a morning in May 2014.
They are captured on security footage holding fishing rods inside a southern Sydney unit block about 7.30am on May 21.
"He said, 'I'll see you bright and early in the morning and we'll go fishing, be ready,' " Mr McNamara told the court on Monday.
The following morning, the pair had a quick conversation on McDonald Street, Cronulla, outside Mr McNamara's unit block.
"Rogerson said, 'Let's go up to Grays Point. It's nice and quiet up there and we can drop him [Mr Gao].'
"[He] said, 'He's going out to sea, he's never f---ing coming back.' "
The court has heard Mr Gao, 20, was shot and killed inside a storage shed in southern Sydney on May 20, 2014.
Mr McNamara and Mr Rogerson are charged with the murder of Mr Gao and accused of stealing the 2.78 kilograms of the drug ice he had brought to sell them.
The pair are pinning the murder on each other.
After Mr Gao was shot, his body was wrapped in a blue tarpaulin and stuffed inside a silver surfboard bag.
The court has heard that, later, Mr Rogerson and Mr McNamara hoisted the body into a boat in the car park of the unit block.
The body was left in the car park overnight until the pair took the boat out.
The next morning, when the pair had travelled for about 40 minutes out to sea, they stopped.
"Rogerson said, 'Give me a hand to push him in,' " Mr McNamara said.
He testified that, after he helped push Mr Gao's body into the sea, Mr Rogerson made a remark.
"I heard Rogerson say, "Oh f---, I should have cut his guts open … Oh well f--- it, he's gone, let's go.' "
On the way back to the shore, Mr McNamara said his co-accused told him to stop the boat.
Mr McNamara said Mr Rogerson was holding a gun, and he fired twice.
He claims Mr Rogerson threatened to harm his family if Mr McNamara said anything to the police.
"[He said], 'Remember, I'll know before [the police] know, just think of your family.' "
The trial before Justice Geoffrey Bellew continues.
Read more: http://www.smh.com.au/nsw/roger-rogerson-said-jamie-gao-was-going-out-to-sea-and-never-coming-back-court-hears-20160418-go8rbg.html#ixzz469yjscWe