THE man arrested on suspicion of the kidnap and murder of Sian O'Callaghan is still being questioned by police.

The news was announced by Detective Superintendent Steve Fulcher, who has been leading the case, to a press conference at Gablecross police station moments ago.

The 47-year-old, believed to be Christopher Halliwell, remains in custody in Swindon.

Det Supt Fulcher said police may need to apply to magistrates in the coming hours to extend the time police can hold him for questioning.