The Garda Commissioner Drew Harris says there will have to be a review of the Garda vetting system.
This comes in light of serious abuse allegations made against Anthony Flynn, the former CEO of Inner City Helping Homeless (ICHH) who took his own life last month.
It is claimed he sexually assaulted several men who the charity had secured accommodation for.
One involved a 21-year-old man classed as extremely vulnerable, who was allegedly brought to the CEO's home by taxi in the middle of the night.
It is believed the charity's taxi account was used.
The alleged victim presented to an adult emergency department the following day, and was transferred to the sexual assault unit.
Commissioner Harris says there must be tight checks on those working with vulnerable people.
"Our vetting legislation, and it is legislation, that sets out the criteria by which individuals undergo vetting.
"Vetting is an intrusive process, and so there are strict criteria as to who can be vetted and who aren't vetted then.
"And so in the light of this incident, we'll obviously have to review that - because one can regard that the homeless are particularly vulnerable.
"And that then maybe an area that needs resolution - certainly we're looking into that".
Commissioner Harris says despite the death of the main suspect, the investigation will continue.
"One of our functions is obviously reporting individuals to the Director of Public Prosecutions.
"If they are deceased, we will still bring together a file so that the matter is properly recorded.
"And also then we can share that, in terms of the learnings that we can [sic] with the Department in respect of vetting.
"But we can also then, for the victims, we can point them toward support services to make sure - in effect - that they are not left out in the cold after this.
"But regrettably, if a principal suspect has passed away, the matter's not going to go to a full term of justice being served."
Additional reporting: Stephanie Rohan