LATE-night revellers evacuated from a Kendal nightclub as a fierce fire raged in hotel rooms above their heads could hold the key to cracking a murder investigation.

Around 150 people were forced to make a hasty exit from Jazz's, off Highgate, in the early hours of Sunday morning as a blaze ripped through the Kendal Hotel claiming the life of an infirm 62-year-old resident.

Norman Picken, who police described as "vulnerable with a poor health history," was trapped and unable to escape the acrid fumes in the four-storey building and died of smoke inhalation, a post mortem has revealed.

Mr Picken, originally from County Antrim, Northern Ireland, had lived in room nine at the hotel for around four months and was known locally as John Wilson.

Police are treating the fire, which started in an unoccupied room, as suspicious.

A murder investigation was launched on Sunday.

"The cause of the fire is unknown and there is no obvious reason for it," said Detective Inspector Ian McBride, who is leading the inquiry.

"We are keeping an open mind on how it may have started."

Detectives working on the case arrested four men this week and three have been released on police bail pending further police investigations, while the other was freed without charge.

Police are keen to hear from anyone who was in the area of the Kendal Hotel and Jazz's prior to the fire starting at around 12.45am on Sunday.

DCI McBride said: "Many people may feel that they can't assist the inquiry for perfectly reasonable reasons.

But I would like to stress that unless they speak to the police regarding the detailed circumstances of this death they may be unaware that they possess vital facts."

Police are appealing for people to come forward with information about the following:

l At around midnight customers entering Jazz's complained of being sprayed with an unknown liquid from a window of the hotel, near to the seat of the fire.

l Between 11pm and midnight two men were spotted arguing in the area of the nightclub and the hotel.

l Two people were seen in the area where the first floor of the Kendal Hotel meets the fire escape and roof of Jazz's nightclub.

"This fire is still very much a mystery," said DI Geoff Steele.

"The fact that people have been arrested does not mean that the police have an accurate picture of what has happened.

We do not."

Forty firefighters from Kendal, Windermere, Milnthorpe and Staveley tackled the blaze at its height and a search of the building was made for four people unaccounted for when they arrived.

Firefighters using breathing apparatus located Mr Picken and he was lowered from his third floor room down a ladder.

Kath Hughes, of Cumbria Ambulance Service, said he was found to be in cardiac arrest when he came out of the building, most probably because of smoke inhalation.

Paramedics attempted to resuscitate Mr Picken in the ambulance but he died at Westmorland General Hospital.

Mr Picken's sister, Kate, told the Gazette from the family home in Dunby, Ballymena: "What has happened to my brother is very upsetting and we want to grieve quietly."

The automatic fire alarm system alerted clubbers to the blaze in the rooms overhead and DJ Ian Trickett, of Hallgarth, Kendal, switched off the music and gave the signal to evacuate.

"It took about four or five minutes to evacuate the club.

They were all stars," he said.

The club was badly damaged by the blaze and owner James Hicks reckons it will be over a month before it opens again.

Six residents from the Kendal Hotel - which takes Department of Social Security referrals - were re-housed at South Lakeland District Council's Town View Fields Hostel.

Some had escaped from the hotel in just their underclothes and they were given clothes by the Salvation Army.

The DSS ensured they had money to buy essentials.

This is the second arson attack at the hotel in 18 months and shareholder Russ Harris said he was "shocked" by what had happened.

An inquest into the death of Mr Picken will open in Kendal next Tuesday.

Anyone with any information should contact Kendal police station on 01539-722611 or Crimestoppers on 0800-555111.