That’s the analogy Christopher Lalli, a Clark County assistant district attorney, uses to describe the situation detectives face when criminal investigations involve passcode-protected smartphones.

Because of recent updates to the encryption on Google and Apple software, newly updated Androids and iPhones no longer can be unlocked, even if law enforcement officers have a warrant. 

Apple, for example, says it no longer can unlock passcodes on devices with iOS 8 or iOS 9. That prevents law enforcement from accessing data stored exclusively on the phone or tablet, such as photos that weren’t synced to the cloud, call records and contact lists.

Police chiefs and prosecutors have criticized Google’s and Apple’s decision to heighten phone encryption, saying it gives criminals the ability to hide evidence. Law enforcement officials say phones often are important resources in cases.

Officials in Clark County are among those concerned about the challenges encryption could pose.

Sheriff Joe Lombardo said the updates to smartphones have hindered investigations. District Attorney Steve Wolfson expressed his concerns in a letter to the U.S. Senate Judiciary Committee, which held a hearing on the subject this summer.

“Simply put, if criminals can hide the evidence of their crimes on their smartphones, and if that evidence is forever beyond the reach of law enforcement, then crimes will go unsolved, criminals will go free and the safety of all of our citizens will be diminished,” Wolfson wrote.

Once the province of only serious cases such as homicides and sexual assaults, increasingly prevalent electronic tools have become valuable resources in most criminal investigations.

“It’s a very common form of investigation on your more routine cases,” Lalli said.

From Apple’s and Google’s perspective, encryption technology is needed to show customers the companies are protecting user privacy, a heightened concern after Edward Snowden’s leak of classified government information. Apple began encrypting by default last fall with the release of iOS 8.

Some advocates also question the extent to which the encryption challenges investigators, who sometimes can access information contained on smartphones from backups, personal computers or phone companies.

Prosecutors, however, maintain that a smartphone search is not a violation of privacy because it requires a warrant.

“The Fourth Amendment of the U.S. Constitution, and similar provisions in state constitutions, protect citizens’ privacy,” Wolfson wrote.

And not being able to access potential evidence can be unsettling for investigators, Lalli said.

“In a thorough criminal investigation, you want to reach every viable avenue of investigation,” he said. “Maybe on a cellphone, there’s a photograph that would be helpful.”

Still, despite concerns, Lalli dismissed the notion that encryption might torpedo prosecution of a criminal.

“There are always workarounds,” he said. “Law enforcement doesn’t stop. We keep on going.”