The Disclosures Tribunal has heard that a Garda, who was Noirín O'Sullivan's first whistleblower as commissioner, was allegedly being pushed out of the force by management.
The tribunal is investigating the treatment of Garda Nicholas Keogh, who made a protected disclosure about alleged collusion between gardaí, in particular a Garda A, and an Athlone drug-dealer, Miss B, in 2014.
In June 2014, Athlone Garda Aidan Lyons reported that he was approached by a Liam McHugh on the street about Gda Keogh. Mr McHugh brought up the "general topic of whistleblowers" to Gda Lyons.
Gda Lyons reported that Mr McHugh said: "The bald guard came over to me the other day and asked if I could remember the time I was searched by the three guards and €800 was stolen from me and spent drinking in the Castle [pub].
"He said that if I wanted to make a complaint about it then he would back me up."
Gda Lyons in his statement says that he asked Mr McHugh if the incident actually happened and was told by Mr McHugh "no, not at all, I'm not going to bring trouble on myself".
Gda Lyons asked if Mr McHugh was talking about Gda Keogh and said that he was and that Gda Keogh told Mr McHugh that "he was there himself when it happened and he would back me up if I wanted to make a complaint".
Gda Keogh stated that he was then called into the office of Garda Superintendent Noreen McBrien and was told that she was "investigating another complaint against him" but that he had no idea what it was about.
Gda Keogh said that Supt McBrien told him she was "sending persons out to get statements from Mr Hugh and from Olivia O'Neill".
Miss O'Neill is a woman who had commented to Gda Keogh about Athlone gardaí colluding with a drug-dealer, Ms B, because "she did favours for the guards".
Gda Keogh's original complaint was about Garda A's alleged colluding relationship with Miss B.
It was not until August 5, 2014, that Gda Keogh was told the author of the report was Gda Aidan Lyons, who was Garda A's partner at the time.
"There was again no rigorous follow-up or conclusion to this charge" said Gda Keogh in his statement.
"It appeared to be just another false allegation left in the ether and used to black and cause apprehension in me.”
"It was inscrutable, was dropped out of nowhere and went nowhere."
Gda Keogh said that he believed that gardaí under investigation got Gda Lyons, who was "a clean pair of hands, and got him to write this nonsense [the report]."
Gda Keogh told Judge Sean Ryan that he didn't believe the conversation between Mr McHugh and Gda Lyons happened nor did he believe the incident even happened, as he would have been implicated in a theft and yet there was "no attempt" to identify the other two gardaí.
"This is all in the first month [since making his disclosure]," Gda Keogh told the tribunal, "and all this stuff is flying around." He said he thought it a "completely vindictive" attempt "to set me up".
"I made my disclosure on 8 May, 2014. The day after the acting commissioner [Noirín O'Sullivan] made a statement that dissent was not disloyalty.
"I was Noirín O'Sullivan's first whistleblower and then all this stuff comes out, emanating from the chief in Mullingar."
Gda Keogh said that he was convinced "they" wanted him out and that they looked for any "Mickey Mouse" reason to do so.
"I had to stay in Athlone," he said. "The main investigation had become a priority - it's become my life."
Mr Diarmaid McGuinnes SC asked who the "they" are that he references in evidence.
"Garda management," said Gda Keogh. "Noirín O'Sullivan is the commissioner. Ultimately, she is in charge of An Garda Síochána at the time this is going on."
A new superintendent, Patrick Murray, took up his position in Athlone in March, 2015,
Gda Keogh alleges that Supt Murray put in place a "regime of excessive supervision" over his work and a liaison sergeant was appointed.
Gda Keogh said that he had no problem with the sergeants he dealt with but that he believed that "Superintendent Pat Murray was targeting me".
Supt Murray told Gda Keogh in March that his travelling expenses could not be paid until he properly taxed and back-taxed his vehicle .
Gda Keogh told the judge that he was driving a two-seat Landrover Freelander and was paying commercial tax on it as he had always done so.
"I pointed out that the NCT would not process my van as private - it had no back seats, was used for police duty and to carry dogs," said Gda Keogh, who added that other gardaí had been given a two-month "amnesty" to sort out vehicle issues "but I don't".
The tax issue was later resolved and back-taxed and Gda Keogh's travel claims approved.
In a statement to the tribunal Supt Murray rejected Gda Keogh's accusation of a "vindictive disciplinary procedure" and added that he issued five other 'Regulation 10 notices' regarding members' private vehicles during that period, including to one other member who also had to back-tax his vehicle.
Gda Keogh continues his evidence tomorrow.