Defence lawyer Mike Antunovic was addressing the jury at the High Court at Palmerston North.
His client, Andre Gilling, was one of the two men accused of murdering Mr Waipouri on December 23 last year.
Co-accused Ashley Arnopp changed his plea to guilty on Monday.
Throughout the trial Gilling had maintained his innocence, and said he had no involvement in the attack - except to shake Mr Waipouri - urging him to get up.
Tripping over Mr Waipouri's legs, as he lay bloodied on the floor of his Rangitikei Street flat, had caused the cuts to his nose and a blackened eye.
Mr Antunovic conceded that forensic evidence heard at the trial "did not paint a pretty picture" for his client.
It would never be known whether a single or multiple blow killed Mr Waipouri.
This was alluded to as a "spectrum of possibilities" in evidence by pathologist Katherine White.
The Crown hadn't proved in its case that any violent injury inflicted by Gilling caused Mr Waipouri's death, Mr Antunovic said.
Assaulting a corpse couldn't be ruled out, but this didn't make Gilling a killer, Mr Antunovic said.
If any member of the jury was uncertain about Gilling's role in the death, it followed that the Crown had failed to prove its charge, Mr Antunovic said.
A gut feeling or suspicion of guilt was insufficient to convict a man of murder.
In summing up, Crown prosecutor Ben Vanderkolk said the only distinction between the two accused was that Arnopp had changed his plea.
Both men played an equal part in what Mr Vanderkolk described as an "explosive episode of violence".
Gilling, like Arnopp, had "murderous intent" to cause Mr Waipouri grievous bodily harm.
And further, he must have known that his actions were likely to cause death, Mr Vanderkolk said.
"You can be sure the accused is guilty of murder," Mr Vanderkolk said to the jury.
Statements given to police characterised Gilling as a "practised and cunning liar", whose "consistent approach" was to blame Arnopp.
Mr Waipouri's DNA was found on Gilling's clothing, shoes and bare legs.
A fresh abrasion on Gilling's instep was also found to contain blood from Mr Waipouri.
The jury of seven women and five men is expected to retire to consider Gilling's fate after Justice Alan MacKenzie sums up today, 10th day of the trial.
The case so far
* Mr Waipouri died from a "multiple application of blunt force trauma" in a sustained attack lasting about an hour at his home. The cause of death was attributed to severe head and neck injuries.
* Both accused were arrested at the scene and are said to have been socialising with Mr Waipouri at his flat the night before. No one else was involved in the attack.
* Those accused are said to have consumed a toxic mix of alcohol, party pills and cannabis in the lead- up to Mr Waipouri's death.