The NCA investigation into what happened in the town between 1997 and 2003 has now engaged with 133 victims and survivors but investigators say they are confident that Professor Alexis Jay was right when she said in her report two years ago that the total number is around 1,400 .
And the 70-strong team, which will soon expand to more than 100, say they believe the number of potential suspects also runs into the hundreds.
The investigation - called Operation Stovewood - was set up at the invitation of South Yorkshire Police in December 2014 and is really an umbrella operation for a range of more focused inquiries like the one which came to end at Sheffield Crown Court on Monday.
Senior investigating officer for the NCA, Paul Williamson, said there are currently 17 individual inquiries within the overall Stovewood investigation.
Mr Williamson said 38 people have so far been designated as suspects but this is just the beginning.
Asked about a previous NCA estimate that there would be around 300 different suspects involved in Stovewood, he said: “I’m confident there are hundreds of potential suspects. There are many more we have to identify in coming months and years.”
Nine people have so far been arrested, he said.
And Mr Williamson insisted that the team was making good progress gaining the trust of victims and survivors.
He said: “We have no reason whatsoever to dispute the figures quoted by Alexis Jay of 1,400.
“Indeed our analysis shows that that is going to be pretty much accurate.”
He said: “It is huge but I’m confident that the NCA is able to deliver the service to victims and survivors that they deserve and we are able to identify and arrest offenders in due course.
“That’s just going to take some time.”
He said: “We’ve given our positive commitment as a National Crime Agency, as a minimum, to engage with them. And, if we offer them the appropriate support and advice and they come out of it feeling in a better place, that, for me, is equally as successful as obtaining convictions.”
Mr Williamson said the inquiry is the biggest in the UK into the exploitation of children and his team has identified more than 11,000 lines of inquiry.
He is currently in charge of a staff of 74 but he has funding for this to rise soon to 117.
He said: “I am determined to identify and bring to justice all those who have abused children in Rotherham in the period covered by Operation Stovewood.
“The scale and complexity of the investigation is extremely large and it will take a number of years to complete. We are working with South Yorkshire Police and other agencies to identify any suspects who may still be active today in order to reduce the potential of further offending. Operation Stovewood will make further arrests this year.”