The Disclosures Tribunal has heard that no evidence has been found on various phones, devices and Garda IT systems to support the allegation of a senior Garda smear campaign against whistleblower Sergeant Maurice McCabe.

Forensic Science Northern Ireland (FSNI) said there was no evidence found to support the claims made by former head of the Garda press office, Superintendent Dave Taylor, that he was directed by former Garda Commissioner Martin Callinan to smear Sgt McCabe and that this was done with the knowledge of former Garda Commissioner Nóirín O'Sullivan.

The FSNI told the inquiry of examining eight phones, two laptops and one iPad used by Mr Callinan, Ms O'Sullivan and Supt Taylor.

It also examined various garda computer systems, including Pulse.

The FSNI examined two phones from Mr Callinan, three phones from Ms O'Sullivan, three phones from Supt Taylor and one iPad belonging to Ms O'Sullivan along with one laptop from Supt Taylor and one from Mr Callinan.

The laptop used by Mr Callinan had been bought for personal use and had been wiped in accordance with garda rules.

The inquiry has previously heard that 12 of 15 phones of interest have gone missing.

These include all three phones used by Supt Taylor while he was in the press office.

Nine out of eleven laptops have also not been found.

Sgt McCabe has told the tribunal that Supt Taylor told him that he was smeared by text but Supt Taylor has alleged that negative briefing was not done by text and was never written down.

Under questioning from Mr Justice Peter Charleton, Elaine Strachan of the FSNI said a year and a considerable amount of time had been spent analysing the devices.

The systems were searched for various keywords including - McCabe, Maurice, Ms D, rat, whistleblower, child, child abuse, kiddie fiddler, negative publicity, reputation and RTÉ.

The tribunal heard of a text sent from Supt Taylor to Mr Callinan on 28 March 2014 just after the commissioner had retired suddenly.

Supt Taylor said he was sorry for the way the commissioner had been treated and it was despicable.

Mark McConnell of the FSNI told the tribunal that seven files relating to Sgt McCabe were found on the group share files of the Garda Commissioner's office.

The tribunal heard that a number of these files related to issues of policing in Cavan-Monaghan.

Mr McConnell told the tribunal that searches of a Garda IT system which records correspondence recovered two entries relating to Maurice McCabe.

One related to correspondence from the Assistant Commissioner Northern Region’s office in Sligo, on a Tusla notification referral about an allegation of abuse against Sgt McCabe.

The correspondence was received by the Garda Commissioner’s office on 16 May 2014.

The tribunal has previously heard evidence in relation to how a Tusla file was created in error after a 2006 allegation against the sergeant, which had been dismissed by the DPP, resurfaced and was incorrectly recorded as a more serious allegation.

The other document related to the Fixed Charge Penalty system, but the tribunal heard no electronic copy of the document was available.

The tribunal has adjourned for the day.

Tomorrow the tribunal will hear from other witnesses on the examination of two other garda IT systems classified as "privileged systems", which the FSNI was not granted access to.

Supt David Taylor is expected to begin giving evidence on Monday.

Additional reporting: Sinéad Morris