As honeymoon bridegroom arrives home - were couple victims of isle's executioner?

Police investigating the murder of newlywed Catherine Mullany are probing possible links between her killing and a recent execution-style shooting in Antigua.

Police commissioner Gary Nelson said there were similarities between Mrs Mullany's murder and the death of a Syrian man on the island in June.

Tony Louisa, 46, was found face down in a pool of blood in his apartment with a single gunshot wound to the back of his head.

Today police in Antigua told the BBC that they had a "person of interest" was being interviewed.

Mrs Mullany, 31, a doctor, was also killed with a single shot to the head and her husband Ben, a physiotherapist, was shot in the back of the neck.

Mr Mullany, who remains critically ill after he was shot in his Caribbean hotel room, arrived back in the UK early this morning.

He was today transferred to the Morriston Hospital in Swansea, where he is being assessed for in the neurosurgery intensive care unit.

At a press conference this afternoon Dr Pushpiner Mangat, the hospital's clinical director for critical care said that Mr Mullany remained 'critically ill'.

'He has not required sedative drugs at any time over the last 24 hours, yet remains in a coma."

Dr Mangat said that if 31-year-old Mr Mullany remains in a coma it is likely doctors will proceed to brain stem testing.

His air ambulance landed at Cardiff Airport at 3.40am. The body of his wife, who was killed in the attack, was flown back separately today with her parents.

Arrival: Ben Mullany's air ambulance touches down at Cardiff earlier today

Dr Mangat said it was poignant that Mr Mullany  was being cared for in the intensive care unit where his wife had recently worked during her time training to become a GP.

He said: 'Staff at the unit, and across the trust, have been shocked and devastated by the tragic events in Antigua.'

He has not regained consciousness since the attack at the couple's honeymoon hotel and may not know of his wife's death.

Doctors in Antigua have said it will take a 'miracle' for him to survive  -  but his parents Marilyn and Cynlais hope he can be saved.

Coming home: Ben Mullany leaves hospital in Antigua

Yesterday Mr Nelson, brought in from Canada to shake up the force earlier this year, said he understood the decision.

He said: 'If that was my child, I'd do exactly what the parents are doing.'

But Mr Nelson said his force was being hampered by a 'code of silence'. He said: 'People don't want to tell the police.' 

Ben Mullany is loaded onto a plane in Antigua for his flight home to Wales

UK detectives will fly to the Caribbean today to help with the investigation, following a desperate plea for help from Antigua's overwhelmed police force.

A Scotland Yard spokeswoman said: 'The MPS will be sending a team of officers to Antigua today.

'The team, which will include one officer from South Wales Police, will support the local senior investigating officers and have been sent following a request from the Antiguan authorities received through the Foreign and Commonwealth Office.'

Mr Nelson has confirmed that Mr Mullany was shot with a handgun in the back of his head and that the bullet remains lodged in his head.

He said police had questioned 31 people and taken 10 statements. Four people remain in custody and around a dozen officers were working on the case.

The couple were married on July 12, barely two weeks before the shooting

He added there was "no evidence" to suggest a local drifter known as Claude had given the couple a tour of the island and denied that the local man had been arrested twice over the incident.

Later, a police source said investigators believed they were hunting for more than one suspect.

Police have seized dozens of guns and ballistics experts are investigating whether the tragedy could be linked to other murders on the island, including the death of Syrian welder Mr Louisa, who had lived in Antigua for nine years.

They believe the Mullanys were the victims of a botched robbery.

Mr Nelson said: 'There are similarities between the two shootings. It is something we are looking at.'

He said it was 'probably not the first time' the killer had struck and said he believed it was 'linked to previous homicides'.

'There's something wrong with this person,' said Mr Nelson.

Mrs Mullany's murder early last Sunday was the tenth in Antigua in the past 12 months. Suspects have been charged in connection with only three of the killings.

Murdered: Catherine Mullany was shot dead while on her honeymoon in Antigua