A care home worker started a fire which killed a "helpless" dementia sufferer just minutes after setting a blaze in a bin in another elderly person's room, a court heard yesterday.

Leanne Devenny, aged 20, is accused of the murder of 83-year-old Irene Watling at the care home where the elderly woman lived in July last year.

Devenny, from Coventry, is also charged with arson in the room of a second patient at the Victoria Mews care home in the city.

It is alleged Devenny, who had worked at the care home for more than two years, started a fire in the sheets of grandmother Mrs Watling's bed as she slept late on the evening of July 9 last year.

Mrs Watling was rescued by fire fighters and rushed to hospital, but later died from severe burns.

Opening the case yesterday, Robert Juckes QC told Northampton Crown Court a police investigation had excluded outside intruders or other staff members from being involved in the two fires.

"We are dealing here with someone who set a fire first of all in Joan Aitken's room and then someone who went on to set a fire in Irene Watling's room," he explained.

Mr Juckes said Devenny's colleagues had seen her in the corridor outside Mrs Watling's room at about the time the fire is believed to have been started.

She later told police she had been filling out paperwork at the time.

Mr Juckes added: "We say the presence of Leanne Devenny in this part of the care home at this time, especially in light of what she told the police in statements subsequently, is significant in this case.

"The prosecution case is that it is possible to exclude others as the possible perpetrators of this fire starting.

"We say the evidence closely points to Leanne Devenny as the person who, for whatever reason, set those fires."

Fire crews were called to the care home in Binley Road at about 9.40pm. Mr Juckes said it was Devenny who made the call but was deliberately vague about the seat of the blaze.

After Mrs Watling was rescued from her room it was discovered there had been a separate fire in the waste bin of Mrs Aitken's room which had luckily burned itself out.

An internal investigation was launched at the home when a knife was found in the bed of a third patient three days earlier.

Devenny also denies a charge of attempted wounding, allegedly caused by leaving the knife in the elderly man's bed when she put him to sleep.

Mr Juckes went on: "The three people attacked were among the least capable of looking after themselves among the 30 people in the home.

"Irene Watling was not capable of doing anything for herself."

Karen Wright, the manager of the care home, agreed that many of the patients were left "helpless" by their medical conditions with most needing help moving, eating or being put to bed.

The case continues.