The woman also admitted a methamphetamine habit of $2000 to $3000 a week.
The suspects all have interim name suppression.
Mr Thompson agreed police used her statement as the sole alibi in the Guy inquiry for a man who committed an aggravated robbery of a service station four days before Mr Guy was killed.
The man was also involved in the burglary of a property the night before Mr Guy's death at which a number of items, including cannabis and a carton of Winfield Gold cigarettes, were stolen.
A cigarette of that brand was found at Mr Guy's driveway, defence lawyer Peter Coles said.
The woman gave a statement that she was with the man at 4am on the morning of Mr Guy's death, and when he woke up.
Mr Thompson agreed police were interested in the man in relation to the Guy murder inquiry,
He earlier told the court police had ruled out links between the murder and drugs or a burglary gone wrong.
Mr Thompson said Macdonald informed police the day after Mr Guy's death that three of the Guys' chocolate labrador puppies were missing.
Scott and Kylee Guy had kept seven puppies from their dog Katie in a cow shed on their Aorangi Rd property.
The Crown alleges Macdonald killed and buried three of the puppies to throw police off in their inquiries.
Mr Thompson said Macdonald told police officers at the scene that the puppies were missing.
"It raised the possibility that there had been a theft or burglary and Scott Guy's murder was linked.''
But investigators soon ruled that out.
"From the scene examination I found it highly unlikely that it was a burglary gone wrong.''
There were "other, more attractive targets'' in rural areas.
The scene examination showed the door to the shed was unlocked and there was no sign that somebody had gone in to have a look.
No property was taken.
Mr Thompson said the shed was an environment where a burglar could go undetected and they would have ample time to detect activity at the house.
There was also no evidence that Mr Guy's ute, which was found running in the driveway with its driver's door open and lights on, had been searched.
Police looked into a number of people of interest but they either had alibis or there was no substance or credibility to any links.
They also looked at links to other burglaries but those cases were solved or found not be linked.
Investigators also ruled out a link between Mr Guy's death and speculation he had discovered cannabis growing on the property.
Police found two plants by the river bordering the property but Mr Thompson said it was a "minor seizure'' and the person who planted them had been prosecuted.
Two seedlings were also found in the cottage on the family farm but that matter was also dealt with.
The trial continues.
