According to documents obtained by the Los Angeles Times, the LAPD was able to bypass the lock screen of an iPhone 5s during the same period that the FBI was in a legal battle with Apple. The report shows that the LAPD found a "forensic cellphone expert" that was able to override the locked iPhone and gain access.
Details about how access was gained are not available, but the police department had tried numerous times to extract the data before this. From Los Angeles Times:
In late January, an investigator with the L.A. County district attorney's office again tried to extract data from the phone but could not, and only obtained the contents of its SIM card. Zych wrote that the phone "was disabled," according to the warrant. The following month, authorities tried to inspect April Jace's iPhone but it didn't even turn on, the warrant stated.
But in March, investigators learned that a forensic cellphone expert could "override" the security features and let authorities view the phone's contents, according to the warrant. A senior investigator with the district attorney's office was able to examine the phone in April, as was Jace's private cellphone expert, the warrant states.
This report surfaces not long after a court ordered a California resident to unlock their iPhone using Touch ID, and of course, the iPhone 5c unlock that the FBI gained.