FORENSIC experts swooped on the house of missing businessman David Guilfoyle this week as police admitted they are close to officially declaring it a murder inquiry.

Detectives are still waiting for confirmation that extensive stains found on the driveway of Mr Guilfoyle's £230,000 bungalow in Royds Avenue, Accrington, are blood but they are convinced a violent assault took place there.

It is now over three weeks since Mr Guilfoyle, 35, vanished without trace and police say the chances of finding him alive are very slim.

Mr Guilfoyle has not been seen since leaving the Grey Horse pub on Whalley Road, Accrington, on Wednesday 25 May after watching the Champion's League final between Liverpool and AC Milan with friends.

Detective Superintendent Mick Turner, who is leading the inquiry, told the Observer: "We have monitored his telephone and bank accounts and there is no indication that he is still out there."

Police have also discovered an unused ticket bought by Mr Guilfoyle for the boxing match between Ricky Hatton and Kostya Tszyu at the MEN Arena on Sunday 5 June.

DS Turner said: "Effectively this is a murder investigation and we are continuing with forensic searches inside Mr Guilfoyle's house, which we hope will finish towards the end of this week."

He added: "We should have the results of previous forensic tests taken outside the house very soon."

DS Turner explained that police believe some kind of weapon was used but have ruled out a gun. None of the neighbours saw or heard anything untoward.

Police sniffer dogs have helped search fields behind Mr Guilfoyle's house, as well as woodland near Hapton and close to the M65 motorway, but have found nothing.

DS Turner said family liaison officers are supporting Mr Guilfoyle's 15-year-old daughter, a pupil at The Hollins Technology College, and her mum Angela Feeley, of Lime Road, Accrington.

He said: "They are in despair and we are continuing to support them. But they are aware they have to be realistic."

A 35-strong team including some of Lancashire's top detectives is working on the inquiry.

More than 500 potential pieces of physical evidence have been recovered from a number of sources, and police are investigating all areas of Mr Guilfoyle's life, including his connection with contraband cigarettes and his tangled love life.

DS Turner said: "We have been speaking to a number of people who are known to dislike him and we feel we are getting closer.

"We are appealing to the public to come forward if they have heard anyone speaking ill of David Guilfoyle.

"We still need people to search their minds, no matter how trivial the information may seem to them."

A 35-year-old man arrested at his workplace in Burnley on suspicion of Mr Guilfoyle's murder was released on police bail last Friday after extensive questioning over a period of 72 hours.

When he returned to the Greenbank police headquarters in Blackburn on Monday his bail was extended until 27 June.

Anybody with information should contact the police incident room on 51212 or Crimestoppers, free and in confidence, on 0800 555 111.