Randall Titus, for Mabena, rejected the State's idea that Maqubela was galvanised to kill her husband Patrick Maqubela and planned his death in the short phone call on Thursday, 4 June 2009.
"It beggars belief that this is the State's theory," he said in closing argument.
Both have pleaded not guilty of suffocating the acting judge with cling-wrap in his Sea Point, Cape Town, apartment on Friday, 5 June 2009.
Maqubela has also pleaded not guilty to charges of fraud and forgery regarding her husband's alleged last will presented at the Johannesburg office of the Master of the High Court.
A flurry of calls
The State had remarked that a flurry of phone calls between Thandi Maqubela and Mabena the day of the acting judge's death was "suspicious".
Maqubela made short calls to Mabena at 08:27, 09:14, 09:41, 13:15 and 14:29. An SMS was also sent from the acting judge's phone to Mabena at 14:27. It read: "Trying to get hold of you."
Titus said the calls were entirely consistent with a person calling to ask for directions, as was Mabena's version of events.
He said Mabena's presence at the acting judge's apartment and the five phone calls on 5 June, were consistent with two distributors conducting business on behalf of Forever Living health products.
"It is reasonable to infer that that telephonic contact was made in order to make the necessary arrangements to visit accused one [Thandi] at her apartment and to purchase a book."
However, Bonnie Currie-Gamwo, for the State, pointed to telephonic communication between the business associates before 4 June.
She said there was a four minute call on 23 May 2009. The following day, there was a three minute call, an SMS from Mabena to Thandi Maqubela and a four second call.
On 30 May 2009, Mabena spent just over 18 minutes talking to Maqubela on the phone.
Nothing linking accused to death
She said cellphone activity also placed Mabena and Maqubela in Sandhurst, Sandton, in Johannesburg, in April 2009.
Titus said the alternate inference on the facts should be drawn, which was that Mabena was innocent.
"There is no evidence, circumstantial or otherwise, from which the inference may be drawn that accused two [Mabena] had the necessary intent, or indeed any motive, to murder the deceased.
"It is common cause that accused two did not know the deceased. The State does not allege that he had a motive to kill the deceased."
He said Mabena's fingerprints and DNA were found on none of the exhibits and there was nothing else linking him to the death.
Murphy postponed the matter until 11 November for judgment.