Fr Beta was accused by Trevor in March 2002 of abusing him when he was 16 while attending a "choice" weekend retreat.
Bishop Éamonn Walsh said Fr Beta comprehensively apologised to Trevor for the incident and accepted full responsibility for it at a meeting in April 2002.
However Trevor's therapist was subsequently telephoned by Fr Beta's support priest to ascertain Trevor's age when the assault took place. Trevor felt this was an attempt to renege on his previous admission and instituted civil proceedings.
These were settled in December 2002.
In September 2002, Fr Beta was ordered by Bishop Walsh to step aside from active ministry.
In July 2002 Neasa informed the diocese that Fr Beta had abused her son, Ben, when he was six years of age. The health board and gardaí were informed of this allegation by the diocese.
In June 2003, Fr Beta agreed to attend therapeutic treatment at Southdown in Canada. He completed his course in July 2004.
The inquiry criticised the delay of some five months between notification of the allegation and the issuing of a precept against Fr Beta requiring him to stand aside from active ministry.
It also noted that Trevor felt the litigation process was unfair.