A Hertfordshire woman may have been dead for three days before being discovered at her warden-controlled home, her family have claimed.
Sylvia Jay, 76, was found in her room at the Beane River View Care Home in Hertford on 23 May.
Relatives said a warden from home operator's Sanctuary Supported Living was supposed to check on her every day.
A spokeswoman said it was "looking into the circumstances" surrounding Ms Jay's death.
Ms Jay's daughter, Linda Jay, said her mother, who had been living at the home for about five years, was not ill as far as anyone knew but "needed to be looked after".
She was found after a neighbour had not seen her for about three days and raised the alarm.
It was another resident who found a duplicate key to her room and the pair found Ms Jay's body.
Linda Jay said residents were supposed to get a knock on the door from a member of staff at 09:30 each morning.
She said this had been happening but "suddenly stopped" and her mother "would have let [her] know" if she had opted out of that scheme.
The family said it is now planning legal action to force answers out of the home's operators.
"Somebody has got to take responsibility, they have got to give me an answer... there is a chance my mum could be alive today," Linda Jay added.
Claire Irwin, from Sanctuary Supported Living, said it would give Ms Jay's family "every support and assistance".
"We are looking into the circumstances and will keep the family fully informed," she said.