Prosecutor Mark Zarifeh yesterday said Crown evidence proving that Tully is the killer is "overwhelming".
Counsel assisting the court, James Rapley in his closing address yesterday said the Crown's case casts doubt and raises uncertainty over whether it has proved beyond reasonable doubt that Tully was the lone gunman.
The jury must put aside any feelings of prejudice or sympathy for the victims of the horrific shooting, the judge said in his summing up.
Justice Mander asked the jury to remain unaffected by emotion in going about their task in an objective and dispassionate manner.
The fact that Tully has been restrained and accompanied in court by Corrections officers is "quite normal", the judge said, and instructed the jury not to read anything into the security measures taken during the trial.
Tully has not been present in court for the majority of the trial. It wasn't until day two that the jury first saw him. He has twice been removed from the courtroom after outbursts before the jury.
Justice Mander said Tully's absence from the trial was "unusual" but not unheard of.
The law allows for a trial to proceed in the absence of the defendant, the jury was told.
The judge deemed it was appropriate and in the interests of justice to proceed with Tully not being in court, although it was "not a step that has been taken lightly".
He asked the jury not to speculate as to why he was absent for long periods.
"His absence must not be held against him."
The jury must not make any adverse inference from Tully's outbursts, the judge said, adding that they must focus solely on the evidence.
Tully has not been represented by a lawyer during the trial, but experienced criminal lawyers, Mr Rapley and Phil Shamy, have been in court as counsel assisting.
Mr Rapley earlier said there were features of the Crown case that have not been satisfactorily answered.
He said some points cast doubt and raise uncertainty and that if the jury is left feeling unsure, then they must find Tully not guilty.
Mr Rapley accepted that the evidence in the trial was "at times chilling" and seeing the CCTV footage from inside the Winz office was "unnerving".
But he asked the jury to remove any feelings of sympathy or prejudice as it considers its verdict.
When they go into the jury room to deliberate he urged them to "robustly debate the matter, listen to each other, analyse and scrutinise the evidence, and go into the jury room with a clear, calm and cool head".
Tully has pleaded not guilty to murdering Ashburton Winz receptionist Peggy Noble, 67, and case manager Susan Leigh Cleveland, 55, inside the Winz office on September 1, 2014.
He also denies attempting to murder two fellow workers Lindy Curtis and Kim Elizabeth Adams and other charges that include two counts of unlawful possession of firearms, and one of setting a man trap.
Crown Prosecutor Mr Zarifeh described the Crown's arguments as amounting to "an extremely strong circumstantial case", with a lot of strands of evidence all woven together that lead to the "inescapable conclusion" that Tully is guilty of the shooting spree.
The killer must have had a "motive or grudge" against Winz or Winz staff in Ashburton to carry out the shootings, Mr Zarifeh said. It would be "nonsensical" to suggest otherwise, he added.
The evidence suggests that only Tully would have had that deadly grudge with Ashburton Winz staff, Mr Zarifeh said.
CCTV from various shops and businesses around Ashburton show the movements of a cyclist in a green jacket with a distinctive white stripe, black helmet and backpack before he chains his black mountain bike up outside the Cass St Winz office at around 9.50am that day.
The man wearing the same clothes is then seen on security cameras inside the Winz office, firing a gun at staff.
Mr Zarifeh told the jury that there is evidence the defendant Tully was seen wearing that "distinctive" green jacket both before the shootings, in the moments afterwards, and when he was apprehended by armed police hiding beneath a thick macrocarpa hedge in a nearby farmer's field seven-and-a-half hours later.
"Why is he hiding inside a hedge? If he had done nothing wrong, why is he hiding?" Mr Zarifeh asked the jury.
"The answer is simple - he's hiding because he is trying to escape after a shooting and he knows that police are looking for him."
An 'inX' sticker, matching ones that the Crown says Tully labelled his possessions with, was found on a spent shell casing at the murder scene, which Mr Zarifeh said is a "clear link" between the accused Tully and scene.
He also highlighted the evidence of forensic scientist and experienced DNA analysis expert Lisa Melia who told the jury that a bike helmet left outside the Winz office by the fleeing gunman had DNA with "extremely strong" scientific evidence linking it to Tully.
The shooter "could only have been" Tully and it would be "ludicrous" to suggest the evidence points to anyone else, Mr Zarifeh concluded.
The jury has broken for lunch after four-a-half hours of deliberations so far.
