The Garda watchdog has lashed out at the practice of gardai investigating their colleagues and said it undermines the Force.
It comes as complaints to the Garda Siochana Ombudsman Commission (GSOC) against gardai reduced last year, with four officers facing charges before the courts.
The annual report by GSOC showed that in 2018 there were 1,921 complaints received - a 1.4% decrease on 2017.
There were 2,944 allegations contained within those complaints - with 1,897 complaints containing 3,949 allegations closed.
GSOC said it is to seek an end to the practice in 2019 and added it leaves the organisation open to attack.
The watchdog report said: “Gardaí investigating themselves runs the risk that the investigation is seen as neither full nor fair.
Footage shows armed gardai restraining man during raid in Monaghan
"This may do a disservice to the investigators but the lack of oversight on such investigations leaves the garda organisation open to challenge.
“It is in the interests of the gardaí to be able to confirm that they do not investigate themselves so that when a decision not to prosecute/discipline a member over alleged misconduct is made, no suggestion of cover-up is able to be generated.
“This is also an issue GSOC plans to pursue in 2019, especially as new legislation is being drafted and particularly in light of the Commission on the Future of Policing in Ireland’s recommendation that all complaints should be investigated by the new oversight body.”
There were 38 referrals from An Garda Siochana in which it appeared the “the conduct of a member of the Garda Siochana may have resulted in the death of, or serious harm to, a person”.
GSOC said 15 of these files related to cases in which people died.
The Garda watchdog also undertook 17 public interest investigations, which were started by the organisation without a complaint or referral by the Garda Commissioner.
There were 17 files sent to the Director of Public Prosecutions (DPP), resulting in four directions to prosecute, nine directions for no prosecutions and four decisions pending at the end of 2018.
There were also 24 protected disclosures were made to GSOC by members and/or employees of An Garda Siochana.
The Garda Commissioner made 74 discipline sanctions on individual gardai following complaints to and/or investigations by GSOC.
The most common matters complained of were abuse of authority, neglect of duty, discourtesy, and non-fatal offences: allegations of a criminal offence listed in the Non-Fatal Offences Against the Person Act 1997, for example assault, harassment or false imprisonment.
GSOC also made a number of recommendations to An Garda Síochána relating to systemic or management issues, rather than behaviour of individuals.
The report said: "The Ombudsman Commission feel highlighting systemic or management issues will avoid recurrence of similar incidents and it’s an important element of oversight.
"The gardai and GSOC also launched a new scheme to resolve “service level” complaints.
The report said: “This local intervention was piloted in a Dublin district and is viewed as a positive step towards working collaboratively to achieve GSOC objectives.”
GSOC also said they sent “a business case for a significant increase in staffing at the start of 2018.”
On November 2 2018, Justice Minister Charlie Flanagan announced 42 posts sought were sanctioned.
