The "majority" of social media accounts that directed racist abuse at Edwin Edogbo following his international debut are based in Ireland, according to ethical data science company Signify.
Edogbo, 23, was the subject of intense racial abuse online after coming off the bench against Italy in the Six Nations last month.
The IRFU has said it will be making an official complaint the gardaí in the coming days over three social media accounts linked to the abuse.
The IRFU partnered with Signify to investigate the case. The company's co-founder Jonathan Sebire told RTÉ's Morning Ireland: "There was a spike of abuse (aimed at Edogbo) that was primarily racist in nature.
"And within that, it covered the gamut of what we might look for, which is explicitly racist, very serious abuse, all the way down into kind of grey areas that go below and into debate about the nature of Irishness, which is something that's happening in a lot of countries at the moment.
"But the serious abuse and the explicitly racist abuse, we would then we would look at that. We report it to the platforms for action, and we would then investigate the accounts that had sent that to see where it's coming from and who it might be coming from, and then if they have a relationship to the client.
"In this case, there was the majority was actually coming from Irish accounts or from fans of the rugby team. There were actually quite a few based in the United States from the expat community, but there was a significant amount that was kind of homegrown and coming from accounts based in Ireland."
Asked why internet companies or social media platforms are not monitoring and policing where comments are coming from, Sebire said: "I think the answer is that they do. It's just that the nature of the conversation often exceeds what they're actually looking for.
"When you're dealing with someone like the IRFU, players are multi-platform and sometimes abuse and or threat can cross across multiple platforms. Any individual platform can only look after their own domain. So companies like ours are there to give kind of a holistic view of what's actually going on.
"Also it may be appropriate for the platforms to take action, but sometimes it's more serious or sometimes it's something that the IRFU or other clients might want to action that the platforms wouldn't want to do themselves."
The IRFU said in a statement on Tuesday: "If any accounts are found to have links to rugby club members, we will not hesitate to take action. There is no place for anyone in a rugby club who behaves in this manner."
Sebire said some accounts involved in the Edogbo abuse "appear to be fans", adding: "If we identify that somebody is a season ticket holder for a club or is regularly purchasing tickets and coming to fixtures, it may be the case that they're subject to banning orders from that or they're stopped from having that kind of access because of the behaviour they've engaged.
"We've handed a number of cases over to the IRFU, and I think they are taking they've made a statement saying that they're taking three of those forward and are going to report those. And it is the case that some of those did appear to be fans. I believe they're considering what the next steps might be in relation to that."
