The woman was 89 when she died in June 2020. Her son, 66, froze the corpse with icepacks and wrapped her in bandages to contain any bodily fluid – before leaving it in the cellar of the home in Innsbruck, west Austria.
The one-year-old corpse was found after a postal worker who delivered the woman’s benefits requested to see the beneficiary.
But the son refused, leading to a police investigation and the discovery of the one-year-old corpse.
The man even lied to his brother and told him their mother was in hospital, police said.
The second son decided against seeing his mother as she suffered from dementia and would not recognise him.
Helmut Gufler, in charge of the police’s social security fraud unit, told public broadcaster ORF: “He covered his mother with cat litter and finally the corpse was mummified.”
Police told ORF the man received £42,600 (50,000 euros) in benefits.
Police found the woman’s body on Saturday.
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It is thought the woman died in the presence of a Romanian nurse in their home.
Police are attempting to contact the nurse but the woman has returned to Romania.
A post-mortem is being carried out but officers said there are no indications of third-party negligence.