Here is a timeline of events surrounding the disappearance of missing three-year-old Mikaeel Kular.
Wednesday January 15
2100: Mikaeel is last seen going to bed at his home address in Ferry Gait Crescent, Edinburgh.
Thursday January 16
0400: Temperatures drop to 2.3C (36F), according to Met Office figures.
0715: Mikaeel's mother discovers he is missing from his bed.
0900: Police Scotland reveal that they have launched a search for the boy. A large hunt is well under way in the Drylaw area and officers are assisted by a police helicopter.
1020: Police release an image of the missing boy, who is described as being of Asian appearance and possibly wearing a beige hooded jacket, blue jogging bottoms, brown shoes and nightwear.
1055: Police Scotland superintendent Liz McAinsh tells reporters there is no evidence to suggest criminality but officers are "keeping an open mind". It emerges that Mikaeel's jacket and shoes are not within his home. Police are looking into whether the boy may have left the home of his own volition. People in the local area are urged to look in their gardens, sheds and any areas where a three-year-old might go. The boy's mother is said to be distraught.
1320: The detention of a man near Mikaeel's home is not connected with the police inquiry, officers say. A large media presence had gathered in the area around Waterfront Gait, where the man was detained.
1430: Coastguard teams and lifeboats search the shoreline in the Cramond and Drylaw area. Neighbours and individuals have also been out searching throughout the day. In the House of Commons, Edinburgh MPs Mike Crockart and Mark Lazarowicz express their hopes Mikaeel would be safely returned to his family.
1600: A dedicated telephone line is established as part of a Child Rescue Alert, supported by all police forces across the UK. The number is 0300 200 0200.
1630: People are asked to urgently check all property including gardens, outbuildings, garages, sheds and vehicles for the youngster as darkness falls. Police issue an updated description of Mikaeel, adding that he has a faded scar on the bridge of his nose and a sore on the left hand side of his mouth.
1700: A full-scale search involving the emergency services and worried neighbours continuing through the evening and into the night as concern grows for Mikaeel.
1830: Gritters are seen out on the streets of Edinburgh, in preparation for a cold night ahead.
2100: A new image of missing Mikaeel is released by Police Scotland. It shows him in the beige jacket he was believed to be wearing when he disappeared.
Friday January 17
Overnight: Neighbours and the emergency services search through the night for the child but there is still no trace of him.
0700: Supt McAinsh says there has been a "fantastic" response from the public and urged anyone with information to contact them.
The search, using specialist officers, police dogs and horses and the air support unit, continues. Police are now said to be "deeply concerned" as they make a fresh appeal for help to find the three-year-old. It emerges that more than 150 calls have been made to the helpline but there have been no confirmed sightings.
1000: Hundreds of people gather at the North Neighbourhood Centre in West Pilton Gardens to help search for Mikaeel.
1030: Work is under way to publish a missing person appeal for Mikaeel on digital billboards across the UK. The adverts are expected to be shown in areas such as train stations and shopping centres.
1345: A "potential sighting" of a child matching Mikaeel's description at 8.30am on Thursday in West Pilton Gardens, Edinburgh is being investigated, police say. The child, described as "small in build and alone" and wearing a cap, is caught on CCTV but it is not confirmed as Mikaeel. Volunteers, including firefighters and mothers pushing prams, take part in a search of the foreshore at Cramond, in north-west Edinburgh.
1745: Assistant chief constable Malcolm Graham says police are exploring whether Mikaeel's disappearance came after a "criminal act". He says that while it is possible he left the family's flat of his own accord, it is "entirely possible that Mikaeel has become subject of a criminal act", and that police are carrying out dual investigations to explore every eventuality.
1815: Mr Graham says all immediate family members have been traced and spoken to by police, and a lengthy timeline of Mikaeel's movements before his disappearance has been established. Ms McAinsh said Mikaeel has not been at nursery since the Christmas break because he has been ill. Forensics officers are seen entering the family's home during the afternoon.
2030: Police thank the more than 200 volunteers who helped during the day, and said their own search would continue through the night.
Saturday January 18
0110: Police reveal that a body believed to be that of Mikaeel was found just before midnight in Fife. Mr Graham confirms that a person has been detained in connection with the death and Mikaeel's family has been informed.