The owners of Brighton's West Pier have said they believe a devastating fire was started by someone strongly opposed to the building's restoration.
Just a metal skeleton was left at the pavilion end after the fire
Flames tore through part of the Victorian pier on 28 March, leaving just a metal skeleton at the pavilion end.
Police said on Thursday they were investigating reports that someone had been seen firing flares into the structure from a dinghy.
Owners West Pier Trust said they believed the fire was arson - started by someone who did not want to see millions spent repairing the structure.
'Put themselves at risk'
Rachel Clark, of the West Pier Trust, said: "It's very distressing that someone would feel so strongly about the pier and that they obviously don't want to see it restored.
"They have gone to these lengths and put themselves at considerable risk, apart from anything else - but I cannot really see any other reason for the fire."
Detective Chief Inspector Steve Fowler, of Brighton and Hove CID, said police were following a number of reports in their arson investigation.
He said: "We are keen to speak to anybody who has any particular sighting around that time or anybody perhaps acting suspiciously - or indeed an idea of how the fire started."
An officer from East Sussex Fire Brigade said the fire had made the 137-year-old pier so unsafe it was too risky to send fire investigation officers on to it so the cause might never be known.
A £30m scheme to restore the pier, which has been closed to the public since 1975, is still going ahead after it was agreed by Brighton and Hove City Council.