- March 18 - Sian O'Callaghan goes for a night out with girl friends in the Old Town area of Swindon, Wiltshire.
- 2.52am March 19 - Miss O'Callaghan is caught on CCTV leaving the Suju club on the High Street. The flat she shared with her boyfriend Kevin Reape, 25, was just a half-a-mile walk away from the club. She did not make it home.
- 3.24am: Mr Reape sends a text message to her mobile phone. Cell site analysis reveals her phone was in the Savernake Forest area, near Marlborough, Wilts, when the message was received. She could only have got from Swindon to the Savernake area - a distance of about 15 miles - by car within the 32-minute time period, police said.
- 9.45am - Mr Reape contacts police and reports his girlfriend missing. He had been unable to contact her after she failed to return home.
- March 20 - Police issue an appeal for information and release a description of the 22-year-old. Detectives say the office administrator's disappearance is out of character and that her family are "extremely worried". Police also reveal they had been searching the 4,500-acre Savernake Forest.
- 10am March 21 - Detective Superintendent Steve Fulcher, leading the investigation, said he was trying to establish Miss O'Callaghan's movements between 3.15am and 4am on Saturday in the Savernake area. He said analysis of mobile phone sites had established that Miss O'Callaghan's LG E900 Optimus mobile phone had activated in a six-and-a-half mile radius of the mast at Cadley.
- 3pm - Mr Reape, supported by his girlfriend's family, makes a tearful appeal at a police press conference for information to find her. He said: "I just want to say how very worried we are about Sian. "She has been missing now for over two days and it's not like her to not come home or contact any of us for such a long time.
"We all want to know where Sian is and we want her home safe and well."
Police rule out Mr Reape as a suspect in the inquiry. Detectives also released CCTV of Miss O'Callaghan leaving the Japanese-themed club on Saturday morning.
- March 22 - Around 400 people, including friends of Miss O'Callaghan and her boyfriend, join the search of Savernake Forest after police appealed for help in combing the dense woodland. An anonymous benefactor offers a £20,000 reward for information.
- March 23 - Using mobile phone technology, police are able to narrow the search of the forest having identified "hot spots" of particular interest. The public are asked not to join today's searches. Mr Fulcher says the inquiry was moving at a "rapid pace" with "significant lines of inquiry being developed".
- March 24 - Specialist dog teams are drafted in to help in the search through woodland. Police appeal for sightings of a green Toyota Avensis estate with taxi markings seen between 3am and 4am and 12pm to 9pm on Saturday between Swindon and Savernake.
A man is arrested on suspicion of kidnap, but Swindon area commander Chief Superintendent Steve Hedley would not reveal how old the suspect was, where he was arrested or whether a car was also seized.
A white police tent is erected in the front garden of a semi-detached house on Ashbury Avenue in Swindon. The house is cordoned off and had three police vans parked outside.
- March 24 - Police confirm they have found two bodies - one of which they believe to be Sian O'Callaghan. A 47-year-old Swindon man has been arrested on suspicion of kidnapping and two murders.
More News stories
- SIAN O'CALLAGHAN: Two bodies found
- SIAN O'CALLAGHAN: Officers search Swindon house
- SIAN O'CALLAGHAN: Man arrested on suspicion of kidnap
- SIAN O'CALLAGHAN: Police tow green taxi away from supermarket car park
- SIAN O'CALLAGHAN: Reward for information now £40,000
- SIAN O'CALLAGHAN: Police reveal Sian's handbag contents
- SIAN O'CALLAGHAN: Family thanks public
- SIAN O'CALLAGHAN: Police hunt for green car with taxi markings