THE 4,500-acre sprawl of Savernake Forest was the centre of the hunt for Sian O’Callaghan and is still part of the ongoing murder inquiry.

Officers originally combed the woodland on Sunday after research suggested Sian’s phone was in the area.

A text message at 3.24am from her boyfriend Kevin Reape registered at the telecoms mast at Cadley, giving detectives a six-and-a-half mile radius to work in.

On Tuesday more than 400 people joined the search of woodland for the 22-year-old.

Friends of Sian and her boyfriend Kevin went on organised police searches of the forest, near Marlborough.

So many people turned out to assist the search effort that by mid-afternoon police had asked for no -one else to come to help.

Volunteers – some who had arrived on two coaches – met at the Postern Hill campsite, on the A346 Salisbury to Marlborough road.

They were divided into groups and each team went off with a specialist police officer to search the dense woodland.

The following day officers searched pockets of Savernake Forest as police turned away members of the public who had turned up to help.

Again on Wednesday detectives continued searching the forest to try and find Sian or any evidence that might lead to her whereabouts.

Research of the mobile phone signal strengths in the area meant certain parts were designated “hotspots”.

Around 60 officers, and another 50 volunteers from Wiltshire Search and Rescue (Wilsar), conducted thorough fingertip searches of smaller areas.

Officers were stationed at the entrance to the Postern Hill camping site, turning away eager members of the public who wanted to resume Tuesday’s hunt.

And coaches organised to transport people from Swindon were put on standby, according to Father Mark Harris, who also led the candlelit vigil at St Barnabas Church, In Gorse Hill, on Wednesday night.

Yesterday, officers with police dogs were due to continue the search at first light and by late afternoon the number of officers in the area had been significantly reduced.