Gardaí are investigating the circumstances surrounding the prison death of a woman who was serving life for the murder of her son.

The body of Ruth Murphy was found by prison officers in her room at the Dóchas Centre at Mountjoy Prison at around 1am.

Foul play is not suspected.

The 48-year-old was jailed for the murder of her only son, seven-year-old Karl Murphy, who drowned on Greystones beach nine years ago.

On 21 June 2001 she had a supervised visit with him at the home of his babysitter, but that evening she escaped with him and they were seen later walking on the beach in nearby Greystones.

Sometime before 10.30pm she drowned the little boy and left him fully clothed on the beach.

A scout leader raised the alarm and Ruth Murphy was found close by in an incoherent state.

A reason for the murder has never been established.

Ruth Murphy suffered from severe alcoholism and was also taking tranquilisers.

Both the Prison Service and the gardaí have begun separate inquiries.