Alexander Pacteau killed Karen Buckley within 20 minutes of meeting her outside a Glasgow nightclub and spent the following two days trying to dispose of her body as police mounted a major search for her.
Pacteau had entered the club just minutes before Miss Buckley and her friends at around 11.45pm on April 11.
He left the club at around 1am alone, telling a steward he was going to get something from his car which was parked around 100 metres away.
A couple of minutes later, Miss Buckley left the club, intending to go home. She crossed Dumbarton Road and ended up near where Pacteau was standing using his mobile phone.
It is not known what transpired between them while there but CCTV showed they walked together towards Pacteau's car.
Further footage then showed his car driving towards the city centre in the direction of Miss Buckley's flat before entering Kelvin Way.
The car was parked there for 12 minutes 46 seconds, during which time Pacteau grabbed her by the neck and hit her repeatedly with a spanner.
She was dead when the car left Kelvin Way at 1.18am.
Footage showed his car heading towards Dawsholm Park, where Miss Buckley's handbag was later discovered. It left the area at just after 2am and Pacteau drove to his nearby flat on Dorchester Avenue.
He took her body wrapped in a sheet into his shared flat, locking his bedroom door.
At around 8am on the Sunday, he used his mobile phone to look up the properties of a chemical called sodium hydroxide, or caustic soda - a high alkaline corrosive substance.
He then travelled to a B&Q store where he bought caustic soda, masks and gloves. He also went to a Poundstretcher store near his flat and bought more of the chemical.
He texted his flatmate to make sure he was out for the day, then returned to the flat and moved Miss Buckley's body into the bath.
Pacteau was found cleaning the hall when his flatmate returned home at around 8pm. He had moved her body back into his locked bedroom wrapped in a duvet.
The following day he left his home at around 5am and went to a nearby canal where he threw the bloodstained spanner into the water.
He then drove to Tesco on Maryhill Road to buy cleaning materials, asking a member of staff to recommend a product for removing blood from a mattress.
He made his first journey to High Craigton Farm, an area familiar to him from a previous job selling fireworks which were kept in a storage unit there.
He stopped off at Tesco in Milngavie at 6.30am and bought white spirit and a lighter to burn clothing.
The 21-year-old then returned to his flat where he used his mobile phone to call a packaging company and ordered a blue 220 litre barrel.
Pacteau collected the barrel from an industrial estate on the other side of the city at 9am before driving to a shop to buy more caustic soda and drain unblocking fluid.
When he arrived back home, he put Miss Buckley's body in the barrel.
He drove to Asda in Bearsden and bought another lighter and lighter fluid. CCTV footage taken at around 10.30am showed his car in the car park with a mattress in the back.
He then drove to the farm and burned the mattress and cleaning items at the same spot as before.
At 11.19am, images were recorded of his car driving in the opposite direction from the farm, heading home.
He poured more chemicals into the barrel before sealing it. He was seen by a witness struggling to put a large blue barrel in his car outside his flat at around 2pm.
After setting off from home, he stopped at the same supermarket and bought two padlocks and more white spirit.
His car is then seen driving towards the farm at 2.35pm. Images showed the barrel in the back of his car.
He arranged to rent a storage unit there and used one of the padlocks to secure the lid of the barrel. Pacteau used the other padlock to secure the door of the storage unit.
He visited a car valet on his way home and while waiting for the Ford Focus to be cleaned, Pacteau used his phone to create an advert to sell his car.
At 5pm, he drove home where police knocked on his door around an hour later.