Police say Usman Khan, 28, attacked people with knives while wearing a fake suicide vest, killing two and injuring three.

Khan was released "on license" from prison last year, after serving about half of a 16-year sentence for his part on a terror plot that sought to blow up the London Stock Exchange and other buildings.

Khan was reportedly attending a nearby prisoner rehabilitation conference put on by Cambridge University's Institute of Criminology.

The Victims

Saskia Jones, one of the two people killed in last week's attack in central London, was an "outstanding" individual who could always "see the good" in people, her university lecturer said on Monday. Jack Merritt, 25, was also killed.

Merritt and Jones were both students at Cambridge University and were active in a program on prisoner rehabilitation. They had been attending a conference about the program when the incident occurred.

The heroes

Video emerged showing how the attacker was taken down by a man with a narwhal tusk, and another armed with a fire extinguisher. 

A Polish chef, according to news reports, grabbed one of two narwhal tusks mounted on a wall at Fishmonger's Hall, where the attack began and pursued the attacker until police arrived. Fishmonger's Hall is located on the bank of the River Thames, near London Bridge.

The attacker

Khan was sentenced to a minimum of eight years in prison in 2012 with a requirement that the parole board assess his danger to the public before release, he was set free in December 2018 - without a parole board assessment.

On Friday, he strapped on a fake suicide vest, armed himself with large kitchen knives and went on the rampage at a conference on prisoner rehabilitation.

It has yet to be confirmed why Khan began his rampage on London Bridge.