At 21:58 BST, a van with the three attackers inside drove onto London Bridge from the north side of the river. The vehicle crossed over, before returning in the opposite direction six minutes later.
When it reached the northern end of the bridge, police said it made a U-turn and mounted the pavement. It then crossed the bridge again, ploughing into pedestrians, including three of those killed.
Xavier Thomas, walking with his girlfriend, was hit by the van, the force apparently knocking him into the river. His body was later found downstream.
BBC reporter Holly Jones, who was on the bridge at the time of the attack, said the van was "probably travelling at about 50mph".
"He swerved right round me and then hit about five or six people," she said.