Concerns have been raised over a "catalogue" of misconduct probes at the PSNI training college in Belfast.
Officers and trainees were disciplined over allegations including assault, discharging of firearms and drug possession.
The probes at the Northern Ireland Police Training College at Garnerville can be revealed after a Freedom of Information request by this newspaper.
Policing Board member Dolores Kelly expressed concern and called for further examination. "Police officers have to have high levels of integrity and set standards. It is somewhat concerning to learn of the catalogue of incidents," the SDLP MLA said.
In the past three years, 20 student officers have been investigated for misconduct - 14 were male and six were female.
The offences include professional duty (integrity), road traffic offences, domestic assault and inappropriate behaviour towards other students.
Meanwhile eight officers - four male and four female - were investigated for a total of 14 matters while working at the police college.
Investigations included drug possession, common assault, negligent discharge of a firearm, misconduct in public office and internal process breaches.
Five matters involving officers led to no further action, two led to written warnings, and three led to 'management action'. Investigations into four matters are currently ongoing.
The PSNI said three of the matters relate to one officer who is currently suspended.
The officer involved in the other matter has been removed from a training role and continues to work administratively within the college pending the outcome of the enquiry.
All matters are subject to decision making and ongoing review.
There are no investigations ongoing with student officers.
Outcomes of matters relating to students included no further action, management discussion, re-coursing, final written warnings and resignation prior to hearing.
One officer was formally redeployed in the past three years.
The PSNI said the majority of matters relate to internal misconduct or performance issues and are investigated by the PSNI's Professional Standards Department or the college's internal management processes.
During the three year period, two matters were referred to the Public Prosecution Service (PPS), but a decision was taken not to prosecute in both cases.
Two other matters involving two student officers were reported to the PPS - one resulted in no prosecution and the other led to an adult caution.
A PSNI spokesman said: "The majority of the completed enquiries have resulted in one of two outcomes, no further action meaning that the allegation was unsubstantiated or management action such as a performance improvement plan."
Misconduct at the college has made headlines in recent years.
Last October it emerged the PSNI was investigating allegations of inappropriate conduct at the facility.
In 2017 there was an investigation into a male trainer who was at the centre of allegations for alleged dishonesty offences.
And in November 2016 police recruitment was suspended temporarily as allegations of cheating at the training college were probed.
The PSNI website states individuals will not be considered for appointment to the PSNI if they have served a custodial or suspended sentence.
Any record of an offence, breaching a court order, or receiving a caution "may be taken into account" when considering an application.
Mrs Kelly said: "One of the things that does concern me is that when you are applying to the police you have to fill out a lot of stuff about having no previous records or convictions and a high level of integrity.
"We have known people who have applied before and we found out some people who, in their misspent youth had, for example, a speeding offence and they could be discounted from applying to join.
"So the issue is then once they are in and they are involved in these types of incidents or behaviour, can they stay in?"
She added: "Not that I'm condoning any of it - but it does warrant further explanation and examination."
Chief Superintendent Philip Knox, head of the PSNI College, said officers and staff are expected to behave "professionally, ethically and with the utmost integrity at all times".
He added: "We expect all of our staff at the college to have role model behaviours that reinforce our organisational ethos and values. These values and standards are instilled into the learning of our student officers as they commence their journey in policing.
"All of our staff, including our newest employees, are supported and empowered to raise concerns if the behaviour of their colleagues, including those in authority, falls below the high standards that we all expect.
"On the rare occasions that the behaviours of our staff falls below these standards we act immediately, with respect to due process, to investigate and robustly address the issues or concerns highlighted.
"The matters will be investigated and may lead to sanction and redeployment or suspension if appropriate.
"As a learning organisation we also understand that staff and students may make mistakes or errors of judgment.
"In those cases the appropriate resolution may be more appropriately addressed through opportunities for reflection, learning and development."