Dozens of people with a sexual interest in children remain anonymous after the messaging app Kik delayed identifying them to Northamptonshire detectives.
The smartphone app is popular with teenagers, but child groomers favour it as they can contact children without giving away their true identity.
Northamptonshire Police says it has been involved in many cases where Kik refused to help detectives trace suspects, leading to a complex and lengthy process in the courts.
One instance was after officers swooped on Allan Barry, who was living in Friars Avenue, Delapre, and Andrej Korda, from London, who had been planning to drug and sexually abuse a toddler.
On Barry's smartphone, police found Kik conversations involving 90 suspects who showed a clear sexual interest in children.
Kik, however, would not give up the identifying information it held on the users without court orders, which often take a year to serve.
It meant Northamptonshire Police officers had to reluctantly drop their efforts to trace the suspects as they would have long moved on by the time the information was given up.
Detective Constable Jason Cullum, who was in the Northamptonshire Police team that caught Barry and Korda, said: "In this case, there was a toddler we'd identified who was about to be drugged and raped.
"We got there before they did it, but on Allan Barry's phone there were numerous others discussing the abuse of children.
"But we'd have to have gone through a legal process lasting about 12 months before Kik would identify users.
"The window of opportunity has been lost. It was a massive problem and we had to let it go."
Five victims and several active abusers were identified relatively quickly by Kik as a result of seizing Barry's phone. But it is the 90 potential abusers still out there - in this one case alone - that is a huge missed opportunity to prevent future harm to children.
The delays in handing over evidence is not because Kik has a lack of information on its users, it is because the firm simply does not believe in freely giving up personal details - hence the common year-long battles.
DC Cullum said that delays often have awful consequences: "There's 12 months of waiting and that doesn't sit comfortably for a police officer, knowing that a child will be being abused all that time.
"There's got to be a point where a child's human rights are a bit more important than that of the abuser."
The only circumstances where Kik will hand over the crucial details is if there is an "imminent threat of death or serious physical injury".
It means that, as far as potential child grooming on Kik goes, the only option Northamptonshire Police has left is to warn mums and dads.
DC Cullum said: "This goes above what anyone in the police can do - it's now a political issue.
"All I can do is issue a strong warning to parents - if your child uses Kik they are at risk."
It does not seem likely that Kik will deviate from its policy any time soon.
Although at time of writing, Kik had not responded to the Chronicle & Echo, the company recently told the BBC: "We take online safety very seriously, and we're constantly assessing and improving our trust and safety measures."
Kik said it will continue to "provide resources to parents and strengthen relationships with law enforcement and safety-focused organisations".
DC Cullum said Kik is simply not set up to be able to handle every police request: "I can see it from their point of view. If they changed their definition [on the circumstances in which they would identify users to police], they wouldn't be able to cope with the number of requests."
He added: "In my opinion, Kik's terms and conditions should be amended to say that if you are sexually interested in children, you are in breach and we will give your information to police."