A few years ago, Tim Beasley opened his front door to discover that a small package had been left on the step.

"I was like 'what the heck is this?'. I opened the box, and went 'oh!', and I immediately threw it away."

Inside the box was a threatening note, alluding to physical violence if he didn't back off.

Beasley works for a US security firm called Semperis, and at the time he was involved in ransom negotiations on behalf of a US government organisation that had been hit by a cyber-attack.

The package delivered to his home in the US was a warning from the ransomware group he had been having to talk to.