Apple will fight a federal judge’s order to help crack the locked iPhone of one of the San Bernardino shooters, the CEO said in a letter to customers Wednesday.

The unlocking of the single cell phone would involve new software that would create a “master key, capable of opening hundreds of millions of locks,” essentially forming new cybersecurity problems, according to Tim Cook, Apple CEO.

“The U.S. government has asked us for something we simply do not have, and something we consider too dangerous to create. They have asked us to be build a backdoor to the iPhone,” Cook said in his statement. “In the wrong hands, this software – which does not exist today – would have the potential to unlock any iPhone in someone’s physical possession.”

Of particular interest to detectives is a window of approximately 18 minutes, in which, authorities cannot account for the two killers’ whereabouts. The couple was chased down and killed in a shootout roughly two hours after they allegedly killed 14 people and wounded 21 others at the Inland Regional Center in San Bernardino, Calif., on Dec. 2.

James Comey, director of the FBI, told the Senate Intelligence Committee’s annual Hearing on Worldwide Threats last week that Bureau experts had been unable to crack open the Farook phone.

Source: Apple Rejects Court Order for ‘Master Key’ into San Bernardino Shooter’s iPhone