Horror mask worn by arson suspect in Castle Bytham
A suspected arsonist, thought to be responsible for a string of attacks on an elderly Lincolnshire couple, disguised himself with a horror mask.
Peter and Sylvia Cox said they were "baffled" about why their 17th Century cottage in Castle Bytham was targeted.
In the last attack, on 4 May, the building was gutted and the couple are now in hiding.
Enhanced CCTV footage of a cyclist seen in the area at the time revealed the Halloween-style mask.
Mrs and Mrs Cox, aged 82 and 74, were alerted by the barking of their greyhound Toby when a lit firework was pushed through their letterbox.
They escaped, but the dog later died.
The couple have said they will not return to the village, where they have lived for 32 years, until the arsonist is caught.
Mrs Cox said: "Even though they are going to rebuild our house, inside it's just a shell.
"It's awful. If they mend it, get it right, we still can't go back home unless they've got the person who did it because they might do it again."
The cyclist suspected of carrying out the attack was seen on the High Street in Castle Bytham at about 0230 BST on 4 May.
The three previous attacks at the house took place in August, October and March, said police.
Crimestoppers is offering a £3,000 reward for anyone who provides information leading to the arrest and conviction of the person responsible.
The case was also featured on the Crimewatch Roadshow programme, broadcast on Monday morning.