Tarapata's partner, Tamara Cassie, who worked at Ezy Cash, was comforted by a friend. She has three children by Tarapata.
The families of Mr Matthews and Mr Fanning stood outside court after the verdict while Detective Sergeant Michele Gillespie read a joint statement on their behalf.
They included Mr Matthews' wife, Arihia, and some of their children, as well as his sisters and brothers. Mr Fanning's son and two daughters were also at court; two had travelled from Australia for the conclusion of the case.
"The guilty verdicts come as bittersweet for both the Fanning and Matthews families who have lost two dearly loved members," the statement said.
They thanked the police, Victim Support and the prosecution for their hard work, and the jury for their "careful consideration of the facts, for their time and for reaching the verdict that they have".
"The past 10 months have been extremely difficult for us and at times overwhelming. We've had to deal with grieving for the loss of our loved ones as well as dealing with the stress of the prosecution process and trial. For this reason we are extremely happy with today's verdict."
Summing up yesterday morning, Justice Pamela Andrews said for the jury to find Tarapata not guilty on the grounds of insanity, it had to be satisfied that "more likely than not" he was suffering a disease of the mind at the time of the killings and that, due to that disease of the mind, he did not know what he was doing was morally wrong.
If Tarapata had caused his own psychosis by methamphetamine use, he was not able to claim a defence of insanity, she said.
However, the jury could find Tarapata not guilty by reason of insanity if he had a disease of the mind that might have been triggered or exacerbated by the drug use.
Ms Gillespie said methamphetamine use was of "incredible concern".
"You just have to look at the number of violent offences that have occurred, and even in the last few weeks we have seen in the courts that many times methamphetamine has been brought up as a reason or a cause."
Tarapata will be sentenced on July 9.