A recently discovered skeleton of an elderly man still wearing pajamas in bed in an abandoned house is believed to have lain undiscovered for more than 15 years.

Police in France are still working to identify the body found in the northern city of Lille, believed to be that of the elderly owner of the property.

The man appeared to have lived alone and appeared to have no relatives.Ā Authorities found stacks of unopened post dating back to 1996 at the house.

The man is reportedly of Spanish origin and was born in 1921, according to the Daily Mail.

"The state of the house suggests it was a peaceful death of someone who died in his bed," public safety official Didier Perroudon said, according to the UK newspaper.

Perroudon added that no one reported the man's absence, and told French news agency AFP that the man was in his bed and his pajamas.

"There was no mess. The house was locked from the inside. Nothing suggests a criminal act," he said, according to AFP.

The remains of the unidentified man were taken away for medical examiners to conduct an autopsy.

The body was found last Friday when a health safety inspector commissioned by the city went to the abandoned house.

"For the moment, we do not know anymore," Perroudon said. "The investigation starts. It will take some time to discover where he comes from, what he did and what his connections were."