Update 5.50pm: A senior Tusla manager has accepted that the buck stops with him in relation to errors made in handling false allegations of child abuse against garda whistleblower Sgt Maurice McCabe.
Gerard Lowry, the Tusla manager for Cavan-Monaghan, denied he was trying to blame others for "catastrophic errors" made by the child protection service.
"I don't accept that analysis, I'm accountable to the service both for what I know and for what I don't know," Mr Lowry said.
"The buck has to stop with you with regard to this," Paul McGarry SC put to the witness on behalf of Sgt McCabe.
"I accept that," said Mr Lowry.
The Charleton tribunal is examining claims that allegations of sexual abuse were used as part of a campaign to smear and undermine the reputation of Sgt McCabe. The DPP decided against pressing charges in the case due to lack of evidence in 2007.
Mr Lowry said a reference to a "no blame culture" in a Tusla report was to encourage others to come forward when things went wrong so he would be aware of what was happening.
Mr McGarry said a letter sent to Mr McCabe's solicitors was "replete with self-justification before you even get to the apology."
The tribunal had previously heard a "copy and paste error" led to Sgt McCabe being wrongly accused of serious sexual assault.
The barrister asked Mr Lowry if he could imagine anything more serious than being accused of raping a seven-year-old child.
"I agree dealing with these situations is hugely emotional and difficult particularly for the adult who receives this letter," said Mr Lowry.
Mr Lowry said he did not accept there was an attempt to conceal all the errors that had been made in handling the sergeant's file.
The tribunal resumes tomorrow.