Apple receives so many police demands to unlock seized iPhones that it has created a waiting list to handle the deluge of requests. ATF agent spent three months trying to “locate a local, state, or federal law enforcement agency with the forensic capabilities to unlock” an iPhone 4S. Apple can reportedly bypass the security lock to get access to data on a phone, download it to an external device and hand it over to the authorities. The Drug enforcement Administration has also faced a similar issue with encryption problem in iMessage chat service as per an internal document.
Source: https://thehackernews.com/2013/05/apple-decrypts-seized-iphones-for-police.html