LONDON—A mysterious figure who used a rare narwhal tusk to help subdue a knife-wielding extremist on London Bridge last month has been identified as a civil servant in Britain’s Justice Ministry.
Darryn Frost broke his silence on Dec. 21, telling Britain’s Press Association that he and others reacted instinctively when Usman Khan started stabbing people at a prison rehabilitation program at Fishmongers’ Hall next to the bridge on Nov. 29.
