Apple rejected claims from US Attorney General William Barr it failed to adequately assist a recent murder investigation, arguing it worked diligently to provide as much information to police as possible.

In a statement to multiple media outlets, the company insisted it offered “timely, thorough” answers to police requests for information from the alleged shooter’s two iPhones, often responding “within hours”.

It added it turned over “many gigabytes of information” related to the queries, including iCloud backups, account information and transaction data, adding “in every instance we responded with all of the information that we had”.

The company did not address whether it had, or would be able to, unlock the devices, a key complaint cited by Barr. However, it noted its engineering teams recently held a call with the Federal Bureau of Investigation to provide unspecified “additional technical assistance”.

Apple took the opportunity to reiterate its stance on the need for strong encryption, stating backdoor access channels favoured by police “can also be exploited by those who threaten our national security and the data security of our customers”.