DC Richards said the two men had not shown any remorse for their offending and believed they had got away with it.
She added: “[Marsh] has deceived these young boys and he’s been able to live this life for many years, but now he’s eventually been caught.”
She said she believed there were more victims who were yet to come forward, adding: “One of the boys said to me that there will be more victims because [Marsh] was so persistent on what he needed from young boys.
“It got to the stage where some of the boys were too old for him so he would then move on to younger boys.”
Charity We Are Survivors has been supporting the victims of Marsh and Whitehead throughout the legal process.
Chief executive Duncan Craig urged anyone who had experienced abuse to come forward.
He said: “You do not need to step straight into a police station. There [have been] many, many, many times where people will come to our service and access support for years before they even think about speaking to the police.
“Please don’t feel like you’re on your own because, even though it does feel like that, I guarantee that you’re not.”
