Police say the blaze was started deliberately
The families of the victims of the Penhallow hotel fire have made a fresh appeal for whoever started it to come forward and "unburden themselves".
Fire broke out at the hotel in Newquay, Cornwall, on 18 August 2007.
The families visited the scene to lay flowers one year on from the blaze which claimed three lives.
Joan Harper, 80, from Stoke-on-Trent, Peter Hughes, 43, from Cheslyn Hay, Staffordshire, and his mother, Monica, 86, were killed.
Detective Chief Inspector Darren Lockley, from Devon and Cornwall Police, said: "I don't think we're looking for a criminal.
"We're looking for someone with a conscience, somebody who's got this burden that's going to increase and carry on increasing if they don't talk about it.
"I don't think anyone anticipated the fire spreading as quickly as it did. I personally don't feel the person responsible intended to kill Monica, Peter and Joan."
He said the situation was still very "raw" for the families: "It's a very difficult time for them. They've come back to the scene, it's very emotional."
The victims' families joined the appeal for anyone who knew how the blaze started to come forward to give them closure.
Joan Harper's great-niece, Jo-Ann Carnwell, said: "She was a central part to our family and that's been taken from us and we want to know why.
The victims' relatives left flowers at the Penhallow Hotel site
"We just want answers to what's happened here."
More than 100 firefighters fought the Penhallow blaze, which started just after midnight.
About 90 people managed to escape from the hotel, including Mrs Harper's twin sister, Marjorie Brys.
But Mrs Harper and Monica Hughes were trapped in the building and died.
Monica's son, Peter, died jumping from the third floor of the 54-bedroom hotel after trying in vain to save her.
Before leaping, he shouted: "I can't move my mum" and "I can't breathe, I can't breathe."
A murder inquiry was launched in January when a police investigation concluded the fire was started deliberately using a naked flame.
Four people have so far been arrested and questioned.
Senior detectives and lawyers will meet later this month to decide whether any charges should be brought.