Brigade – into bequeathing half of his €1m estate to her two children.
Her defence team suggested that Mr Davis suffered memory problems and had somehow "forgotten" leaving half his estate to the Perrin children.
In just under four hours, the jury decided that the octogenarian – who left €2,000 each in his will for Perrin's children after the discovery that he had been tricked – was not suffering memory loss.
Separate charges of deception relating to the will of Mr Davis's wife, Ada, were dropped before Perrin's trial because Mrs Davis's mental state had declined to the point where she was unable to give evidence.
Perrin, of Lambay Court, Malahide, Dublin, had pleaded not guilty to deceptively inducing Mr Davis to bequeath half of his estate to Sybil and Adam Perrin at her office on Fairview Strand on January 22, 2009.
Prosecutor Dominic McGinn said Perrin fought the case using "lies, half-truths and deceptions".
Last night, a brief statement from the Courts Service said that Judge Heather Perrin offered her immediate resignation from the District Court bench.