A fourth boy has been arrested after five teenagers were stabbed at a Halloween party in Hampshire.

Police were called shortly after 22:30 GMT on Saturday to a home in Park Road in Chandler’s Ford where an “unknown group” had gained entry to the event over a garden fence.

One boy, 17, remains in hospital in a life-threatening condition. The other four boys, who all suffered serious injuries, have since been discharged.

A 16-year-old from Southampton has been arrested on suspicion of attempted murder. Police have been given an extra 36 hours to question a 16 and 17-year-old, also from the city, who were held on Monday morning on suspicion of the same offence.

A 16-year-old boy from Bristol remains in custody having been arrested on suspicion of attempted murder on Monday night.

Two witnesses told the BBC a fight started after a group came in over a garden fence, although they said the motive for the stabbings was unclear.

One of the teenagers said: “I was [standing] in the hallway near the exit and I saw someone I know pull up their shirt and say ‘I’ve been stabbed’.

“And then I later saw him lying outside the front of the house with someone compressing his wound.”

The other witness said: “A big group of people started shouting and then a fight broke out and then we just heard the dad tell everyone to leave.

“And that was when we saw someone injured on the floor.”

Police cordoned off parts of Park Road and the adjoining Valley Road.

The five boys who were stabbed had been invited to attend the supervised party.

Hampshire police said officers had carried out searches at three addresses linked to those arrested, two in Southampton and one in Bristol.

The force said several items had been seized, “forming part of our continued investigation”.

It added since the investigation began, a number of witnesses had got in touch and officers had spoken to many of them.

Those who had already been in touch should wait to be contacted.

Anyone with information is still being urged to come forward.

The force said “no matter how small it may seem to you, it may be key to our inquiries”.

Two churches in Chandler’s Ford said earlier in the week they had opened their doors to offer support.

St Boniface in Hursley Road is open 09:00-17:00 through the week, while St Martin in the Wood in Queen’s Road will open Wednesday from 15:00 to 17:00.