The attack which killed Merritt and one other person took place outside of the Fishmongers' Hall, where an event for the five-year anniversary of a Cambridge prison rehabilitation programme, Learning Together, was taking place.
Police on Cannon Street in London near the scene of an incident on London Bridge in central London following a police incident, Friday, Nov. 29, 2019.
The three survivors were not named.
Mr Johnson said Khan was under "various conditions", adding: "He had mentors, he had restrictions on his mobile phone, he had restrictions on internet access".
Law and order tops election agenda Public anger over the latest twist quickly spread to social media while Johnson wasn't the only politician to seize on the outrage ahead of the snap vote on December 12.
Attacker Usman Khan, a convicted terrorist who had secured early release from prison, was shot dead by police after he was restrained by civilians.
"I think it's fair to say we're all shocked and saddened", the minister said.
"We know Jack would not want this bad, isolated incident to be used as a pretext by the government for introducing even more draconian sentences on prisoners, or for detaining people in prison for longer than necessary", his family said.
"Obviously it's early days and there's a lot of investigations that need to be done".
Stephen Toope, the vice-chancellor of Cambridge University said he was "devastated to learn that today's hateful attack on London Bridge may have been targeted at staff, students and alumni attending an event organized by the University of Cambridge's Institute of Criminology".
The British government has launched so-called "de-racialization" programs in an effort to reform jihadis, but the Associated Press reports that it is still unknown whether Khan participated in any such programs.
They reportedly included a convicted killer on day-release from prison and other ex-offenders also attending the criminology event. "He was such a fine young man and his father was very proud of him". Khan was one of a group of nine jihadists who were arrested in 2010 for plotting to blow up the London Stock Exchange. In 2013, his sentence was updated with a 16-year term that allowed him to be released without parole after eight years.
Inmates are usually released half-way through this type of determinate sentence - and time spent in custody before trial may have been taken into account.
Prime Minister Boris Johnson said Sunday the security services were stepping up monitoring of convicted terrorists released early from prison, as the attack became embroiled in the election campaign.