“Look at the situation where the cop in Ferguson last summer shot Michael Brown not long after he was allegedly trying to grab the officer’s gun as he sat in the patrol car,” said Mosbacher. “And the homeless guy who was shot dead in Los Angeles earlier this month, where you could hear the cop saying he thought he was going to take his gun.”

He says those deaths may have been prevented if the officers and the public knew that the handguns chosen for law enforcement personnel could only be fired by the officer and other authorized individuals, such as the cop’s patrol partner.

Holder, vice-president Joe Biden and Obama have previously expressed interest in restricted-access guns. Obama has talked ruefully about America’s abnormally high death rate from shootings, at around 33,000 a year, and the link with a lack of gun control regulations at local, state and federal level.

The technology behind guns that feature biometric identity strips or radio receiver chips is still being refined, and some skeptics worry the devices are more clumsy to handle and slower than a normal gun.