CCTV has shown how the three London Bridge attackers performed a “dry run” over the bridge nine minutes beforehand, according to reports.
Khurum Butt, Rachid Redouane and a third killer drove their white Renault rental van from north to south over London Bridge at 9.58pm before turning back to begin their deadly rampage.
According to sources quoted in the Times, the men likely made the trip to scope out police presence, traffic, and the potential for mass casualties.
Reaching the south side of the bridge, near Borough Market, the attackers then turned the van unnoticed and crossed back over the river, turning again at Monument to begin the assault.
They drove once more from north to south, this time speeding up suddenly midway and veering across to the eastern pavement.
After ploughing into pedestrians, the van returned to the road. Then it swerved over the central reservation before slamming to a halt outside the Barrowboy and Banker pub.
Emergency services received more than 100 calls, the first lodged with ambulance staff at 10.07pm, the Times reported.
The three marauding knifemen, clad in fake bomb vests, flung the van doors open and leapt into the streets, lunging at passersby with long blades.
An officer from the British Transport Police took on the killers armed only with a baton, suffering injuries described as life-altering.
The men burst into restaurants where they stabbed diners, including an Australian woman who has told how she survived being slashed across the neck from behind.
As emergency services arrived at the scene, eight police firearms officers fired a total of 46 rounds at the three men, who were all dead by 10.16pm.
They had killed seven people and injured at least 48.