Accidental fall triggers Johnnie Puna's murderous attack on Mark Beale

Mark Beale, 45, died following an assault in Haumoana, Hawke's Bay. Mr Beale was found on the beach unconscious on February 6.

In a High Court trial at Napier this year a teenager was found guilty of murdering Haumoana man Mark Geoffrey Beale.

Beale, a father of two, was found bloodied and beaten with unsurvivable brain injuries in the seaside settlement on the morning of Waitangi Day and died just after midnight on February 7.

A homicide investigation dubbed Operation Helm saw a team of 35 police comb the coastal community the following day and on February 24 Johnnie Puna was arrested and charged with Beale's murder.

The 19-year-old stood trial in November and was found guilty of murder after the jury deliberated for three hours.

Previously unknown to each other, Beale met Puna in a chance encounter on Haumoana Beach on the evening of February 5.

They had both been drinking: Beale with his home brew vodka in hand and Puna with cans of bourbon and cola mix.

The teenager had been fishing at the beach with his cousin, Leroy Christie, and uncle, Tehungia Puna, who were both called as Crown witnesses during the trial.

Beale shared his alcohol with Puna that night and when this ran out the pair headed to Beale's house for more liquor.

At the trial Mr Christie said he saw Beale accidentally trip and pull Puna down as they returned to the area a short while later.

This, Crown prosecutor Steve Manning said, was the "catalyst" for the fatal attack that followed.

"It seems Mr Puna chose to attack Mr Beale for an innocuous and simple reason. Mr Beale accidentally fell over pulling Mr Puna to the ground and causing him to receive a minor cut to his lip."

It was accepted at the outset that Puna went on to deliver a number of punches and kicks to Beale's head, and that these actions caused Beale's death.

However the intent, or recklessness, in which these were inflicted was the subject of the trial.

The Crown claimed it was murder, by way of Puna either intending to kill Beale or intending to cause bodily injury he knew was likely to cause the man's death.

Defence lawyer Eric Forster said the teenager did not have murderous intent but was young and drunk, and did not realise the injuries could be fatal.

He submitted the appropriate verdict was manslaughter.

In a DVD interview Mr Christie said his cousin had turned to him before the beating and said, "Watch this".

Puna began punching and kicking Beale on the head, knocking him out before waiting for him to regain consciousness to further the assault.

"Something just went over him and just possessed him to keep on going. It was f***ed up," he said.

The assault lasted upwards of 40 minutes, ending with Puna urinating on the man as he lay dying.

In his closing address Steve Manning asked the jury to put on Puna's bloodied shoes and walk around in them.

"Put yourself in Mr Puna's place and ask yourself what else can he have been thinking. What was he thinking as he drove, forcefully, his foot into the face and head, repeatedly, of a defenceless man lying on the ground."

Puna will be sentenced on February 8.