A 14-year-old Waitara girl used Kenneth Pigott's own hammer to bash him over the back of the head while others distracted him, a murder depositions hearing in New Plymouth Youth Court was told yesterday.

Three 14-year-old girls have been charged with the 60-year-old Waitara truck driver's murder on or about March 11 and the unlawful taking of his four-wheel-drive vehicle.

Mr Pigott's body was found on the bank of the Waitara River on March 11.

The girls cannot be named unless a prima facie case is found and the trial is heard in the High Court.

The Youth Court is closed to the general public but five members of the Pigott family were allowed to attend, as were 18 of the girls' family members. Special permission was given to the media to report proceedings.

Crown prosecutor Chris Wilkinson-Smith said the three defendants found Mr Pigott asleep in his vehicle outside Jan's Restaurant in Waitara about 11pm on March 10.

They acted together to kill Mr Pigott and make off with his vehicle.

A 12-year-old girl, who gave evidence through closed-circuit TV, described how she was a member of a Waitara "clan".

On March 10, three of them drank half a large bottle of bourbon and coke in the afternoon. The bourbon was bought for them by their grandmother.

Later that night they noticed a car with its lights and windscreen wipers on, she said.

A man was sleeping in the car. Two of the girls opened up the door and took the keys out and took sandals and a hammer from the vehicle, the witness said.

The three 14-year-olds then talked about stealing the car. They talked to the man who woke up and angrily asked for his keys.

The 12-year-old said she listened as the three 14-year-olds plotted how they would hit him.

"(One defendant) said: 'Should I hit him on the head while he's in the car?' My heart went beep, beep, beep, beep.

"(Another defendant) said, 'Don't hit him with the hammer, just knock him out with your fists or let me knock him out with my fists'."

The girl who had the hammer went around the back of the vehicle. A second distracted Mr Pigott by talking to him. The third went for a ride on her skateboard, the 12-year-old said.

The witness said she was about five steps away from the car when the attack occurred.

She said she didn't see the blows because she put her head into the hood of her jacket. She heard a sound like a big brick being thrown on to the ground. When she looked back Mr Pigott was on the ground.

The girl with the hammer yelled at the others to help her drag him. The three defendants then took turns to drag the man over the bank towards the river and "chucked him in", she said.

A 13-year-old boy with them threw the hammer in the river.

The three girls told her and the boy to jump in the car and after a short drive dropped her off at home, the girl said.

The depositions hearing is expected to last for a week, after which JPs Tom Ryder and Fred Cox will decide whether there is a prima facie case to answer.