Detectives investigating a hotel fire which killed three Staffordshire people have said they will not rest until they catch the arsonist responsible.
It is the first anniversary of the fire at the Penhallow Hotel in Newquay, Cornwall, which last summer claimed the lives of Joan Harper, 80, Peter Hughes, 43, and his mother Monica, 86.
Four people were arrested in connection with the blaze, which firefighters said was the worst in Britain for 30 years.
Senior investigating officer Det Chief Insp Darren Lockley said he believed that, one year on from the incident, the burden of what happened would be weighing heavily on the person responsible.
DCI Lockley said he does not believe the person intended to kill and stressed they must come forward and explain to the families what happened. He said: "It will take a very brave person to come forward.
"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."
Mr Hughes, a teacher from Cheslyn Hay, Staffordshire, jumped from the third floor of the 54-bedroom hotel after trying in vain to save his mother. Before leaping, he shouted: "I can't move my mum" and "I can't breathe, I can't breathe."
Ms Harper, of Stoke-on-Trent, was also trapped, while her twin sister, Marjorie Brys, was one of more than 90 people who escaped.
A murder investigation was announced by police who said the fire, which ripped through the building in the early hours of Saturday, August 18 last year, was started deliberately by a naked flame.
During the investigation detectives have analysed more than 3,500 documents including 1,000 statements.
DCI Lockley said: "It is a year on but it is still very raw for the families. They're still looking for answers so they cannot properly go through the grieving process.
"The case is still ongoing and it will not be closed until we have caught the person responsible.
"The person responsible would probably hope that the burden of this incident would have diminished but it will have got heavier. They have the opportunity to come forward and explain to the families what happened."
The four people who were arrested in connection with the fire include the hotel's former general manager Andy Woollam, 42, and his wife Sarah, 36, who were arrested and released on bail to return on September 2.
Two men, who have not been identified, were also arrested and released on police bail to return on the same date.