Met Police officers spent thousands of hours trawling CCTV footage to capture Sarah Everard’s killer.
Detective Chief Inspector Katherine Goodwin, who led the investigation, said as soon as Ms Everard was reported missing the case “rang alarm bells”.
She ordered divers to examine Clapham Common ponds and officers began trawling through a huge pile of CCTV footage.
Data from Ms Everard’s phone placed her at Poynders Court on the South Circular just before 9.30pm.
Detectives worked out her route to Brixton and concluded that she must have gone missing on a stretch of road that was no more than 300 metres long.
Ms Goodwin told The Times: “On this length of road we knew that Sarah must have gone missing. But what we didn’t know was how or under what circumstances.
“This small area became the focus of the investigation. Had she turned off the road north or south? Had she got into a bus or a taxi? Had she met someone and gone into a house in that area? We began to methodically box off that small area establishing whether she had diverted, whatever explanations there might be.”
After a meticulous analysis of bus camera video there was a breakthrough on March 9, six days after Ms Everard was killed.
CCTV from a bus showed her standing next to a white car with hazard lights flashing.
The team discovered it was a rental vehicle and traced the car back to Wayne Couzens, a serving Met Police officer.
Ms Everard’s body was discovered in a pond in Kent on March 10. It had been badly burnt.
Ms Goodwin said: “I will never forget the moment one of my team came running into my office, closed the door and told me the renter of the car was a police officer.
“I was in absolute shock.”
In total officers reviewed more than 2,000 hours of CCTV and recovered 1,727 items of physical evidence, 95 items of digital evidence and 295 forensic samples in their search for Couzens.
He will die in jail.