A man who had covered himself in petrol became a human fireball after police shot him with a Taser.
A police watchdog will investigate whether firing the weapon at Andrew Pimlott, 32, caused fatal burns.
Mr Pimlott suffered serious injuries in the incident on the evening of April 18.
He was taken to hospital and subsequently transferred to the specialist burns unit at Frenchay Hospital in Bristol, where he died five days later.
The Independent Police Complaints Commission (IPCC) said two Devon and Cornwall Police officers responded to a 999 call from a caller who said that Mr Pimlott was in a garden with a can of flammable liquid.
Shortly after the police arrived he sustained serious burn injuries and an ambulance was called.
An officer deployed a Taser during the incident in Honicknowle, Plymouth, the watchdog said.
IPCC Commissioner Sarah Green said: “My condolences go to Andrew’s family and friends for their loss.
“This must be a very difficult time for them and we have appointed a family liaison manager who is ensuring the family are kept informed.
“Our investigators have already carried out a number of actions, including interviewing the two police officers who attended the incident and ensuring relevant evidence has been secured.
“A post-mortem was carried out yesterday and further forensic analysis will be carried out.
“The IPCC had informed the coroner of our investigation and we will share our report in due course.
“Our investigation will be looking at what information was known to the officers attending the scene, the officer’s rationale for discharging a Taser on a person known to be doused in flammable liquid, whether the discharge of the Taser caused the fuel to ignite and we will look at training and policies.”
In separate statements, Mr Pimlott’s family paid tribute.
His parents wrote: “Dear darling son Andrew, you were a fantastic son to us, you will always be in our hearts and thoughts.
“We will never forget you. Be in our heart forever and always, we send a million kisses up to heaven.
“All our love Mum and Dad. xxx”