A man has been jailed for sending a homemade bomb to the offices of a London cryptocurrency company after employees refused to reset one of his passwords, police have said.

Scotland Yard said detectives could “only identify one possible reason” for the Swedish national to target Hackney-based firm Cryptopay.

Customer Jermu Michael Salonen, 43, had emailed the company to ask them to change his password in August 2017, but they refused, saying it would contravene their privacy policy.

Download the new Independent Premium app

Sharing the full story, not just the headlines

Salonen, 43, has been sentenced to six-and-a-half years in prison at Stockholm District Court.

The 43-year-old sent the device in a padded envelope to two employees of Cryptopay, which is based in Hackney.

A man working at the office block began opening the envelope on 8 March this year, but became suspicious of the contents and called the police, according to Scotland Yard.

Specialist officers were sent to examine and make safe the bomb, which the Met said was “viable” and could have killed someone.

Detectives from the Met Police Counter Terrorism Command investigating the parcel discovered the parcel was sent in November 2017 and had remained in the office unopened for five months.

Forensic experts discovered DNA traces on the devices, but they did not match any samples held in police databases, so the Met contacted Interpol to request that member countries check their systems.

The DNA traces were found to match Salonen and Swedish police arrested him on 12 May 2018.

He was also arrested on suspicion of sending a number of letters containing death threats to high-profile people in Sweden and one in London.

The Swedish prime minister Stefan Löfven and a number of ministers in the government received letters at their homes that said: “You will soon be dead”.

The letter sent to a businessman in London contained a harmless white powder. Authorities intercepted the correspondence Swedish sorting office.

Swedish authorities, supported by the Met Counter Terrorism Command searched Salonen’s address and found a number of bomb components.

On Friday a judge in Sweden found Salonen guilty of attempted murder for sending the bomb. He was also convicted for sending a number of malicious letters, for which he was sentenced to a further six months’ imprisonment.

Commander Clarke Jarrett, head of the Met Police Counter Terrorism Command, said: “Salonen seemingly made and sent a device that had the capability to seriously harm and even kill over something as inconsequential as a change of password.

“Fortunately the bomb did not detonate. It was due to sheer luck that the recipient ripped opened the package in the middle rather than using the envelope flap which would have activated the device”