A murder inquiry has been launched in Northern Ireland after the death of a prison officer.

Adrian Ismay died in hospital yesterday almost two weeks after a bomb was detonated under his van as he drove to work in east Belfast.

Following a post mortem examination, detectives from Serious Crime Branch have launched the murder investigation.

The PSNI say the post mortem concluded Mr Ismay died as a direct result of the injuries sustained during the explosion on Friday March 4th.

Detective Chief Inspector Richard Campbell said: "Today is yet another difficult day for the Ismay family, his friends and colleagues as they struggle to come to terms with the events of the past 12 days".

"We have spoken to the family this morning and advised them of this development".

"We are also liaising with the Public Prosecution Service in relation to the individual who is currently charged with attempted murder and causing an explosion with intent to endanger life", he added.

"They are evil people"

Tributes have been paid to Mr Ismay.

Speaking from Washington DC, Taoiseach Enda Kenny said: "Such attacks can have no place in a civilised, inclusive society and we must continue to work at all levels to copperfasten a future for Northern Ireland that is committed to the democratic process and the rule of law and is free from violence and intimidation".

Foreign Affairs Minister Charlie Flanagan said it was "a callous and cowardly attack on the entire community".

While Justice Minister Frances Fitzgerald added: "I condemn in the strongest possible terms the people who carried out last week's cowardly bomb attack".

"They are evil people who reject the democratic will of the people across this island. An Garda Síochána and the Police Service of Northern Ireland will continue to work closely together to counteract the persistent threat that these people represent".