Gardai and prison authorities are investigating the death of a 21-year-old prisoner at Mountjoy Prison.
This brings to six the number of prisoners who have died in custody this year.
The man was found dead early yesterday morning in a cell he had been sharing with three other prisoners.
According to a spokesman for the Prison Service, one of his cellmates raised the alarm after 5 a.m. The man was rushed to the Mater Hospital where he was pronounced dead at about 6 a.m.
The prisoner had just been moved from Clover Hill Prison, where he had been held on remand. He had just been sentenced to 10 months for receiving and handling stolen property.
The spokesman said there was nothing to suggest the death was caused by suicide but he said that they were keeping an open mind until a post-mortem was carried out.
Of the other five prisoners' deaths this year, two were attributed to self-infliction. Another was caused by stabbing while the other two were due to natural causes. Last year, seven prisoners died in custody. Six of these deaths were self-inflicted. Five prisoners died in custody in 1998.
Due to the growing concern over prison suicides, a suicide awareness group has been set up in every prison in the State. The National Steering Group on Deaths in Prison has found the majority of prison deaths are suicides. Between 1990 and 1997, 56 per cent of deaths in custody were suicides. Some 27 per cent were due to drug overdoses or prisoners choking on their own vomit, while 17 per cent were due to natural causes.
The steering group has noticed a dramatic increase in the numbers of deaths due to natural causes and drug overdoses. This reflects the increase in the numbers of older people committed to prison for sex offences, as well as the increasing use of drugs.
