Apple's PR nightmare on the issue of warrants for iPhones just keeps getting worse.

On Sept. 18, Tim Cook published an open letter to Apple customers that detailed how secure the company's new mobile operating system, iOS 8, is.

The FBI and local police forces have grown concerned over the level of encryption in Apple devices, as they claim that it's becoming difficult for them to access iPhones even if they have a court-ordered warrant, if the owner refuses to give up their passcode.

Now, the chief of detectives for Chicago's police department has issued an alarming statement on the effects of Apple's heightened encryption.

Speaking to the Washington Post, John J. Escalante said, "Apple will become the phone of choice for the pedophile. The average pedophile at this point is probably thinking, I’ve got to get an Apple phone."

Previously, James Comey, the director of the FBI, said "What concerns me about this is companies marketing something expressly to allow people to place themselves beyond the law."

And before that, Ronald Hosko, the president of the Law Enforcement Legal Defense Fund and a former assistant director of the FBI's criminal investigative division, worried that people would be killed if police were unable to speedily unlock iPhones to get encrypted information on them.

The key change in iOS 8 is that iMessage texts are encrypted on the iPhone. As long as they're not stored in the unencrypted iCloud backup system, the only way to get them is through the user's passcode. Even a warrant won't unlock them.

Most iPhone users use iCloud, and iMessages are stored in iCloud, so it's not clear just how big a universe of criminals the encryption in iOS 8 would include. And police have access to Elcomsoft products, which are designed to help law enforcement crack password-protected iPhones.

The point being, this is a PR issue rather than a tech issue at the moment: Apple's new stance on privacy and encryption has gone down poorly with law enforcement, but it's not yet clear whether criminals are actually able to take advantage of Apple's products the way they fear.